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Motivated by experimental reports on chirality induced spin selectivity, we investigate a minimal model that allows us to calculate the charge and spin conductances through helical molecules analytically. The spin–orbit interaction is assumed to be non-vanishing on the molecule and negligible in the reservoirs (leads). The band structure of the molecule features four helical modes with spin-momentum locking that are analogous of edge-currents in the quantum spin Hall effect. While charge is conserved and therefore the charge current is independent of where it is measured—reservoirs or molecule—our detailed calculations reveal that the spin currents in the left and right leads are equal in magnitudes but with opposite signs (in linear response). We predict that transport currents flowing through helical molecules are accompanied by a spin accumulation in the contact region with the same magnetization direction for source and drain. Furthermore, we predict that the spin-conductance can be extracted directly from measuring the (quasi-static) spin accumulation—rather than the spin current itself, which is very challenging to obtain experimentally. [ABSTRACT FROM AUTHOR]

Motivated by the multiferroic effects and quantum magnetization plateaus in the skew chain antiferromagnets T 2 V 2 O 7 (T = Ni, Co), we have conducted a detailed density function theoretical study on Co 2 V 2 O 7. The results show that the nearest-neighbor interchain interaction (J 3 / k B = − 35.57 K) is not much greater than the intrachain interactions (J 1 / k B = − 19.54 K and J 2 / k B = 27.55 K), showing the absence of interchain dimerization of the Co ions. This indicates that the "dimer+monomer" model used for Ni 2 V 2 O 7 [Cao et al., Phys. Rev. B 106, 184409 (2022)] is no longer applicable to Co 2 V 2 O 7. Finally, the exact diagonalization of spin Hamiltonian, including anisotropic exchanges, produces the experimentally observed 1/2 and 3/4 magnetization plateaus. [ABSTRACT FROM AUTHOR]

Motivated by the multiferroic effects and quantum magnetization plateaus in the skew chain antiferromagnets T 2 V 2 O 7 (T = Ni, Co), we have conducted a detailed density function theoretical study on Co 2 V 2 O 7. The results show that the nearest-neighbor interchain interaction (J 3 / k B = − 35.57 K) is not much greater than the intrachain interactions (J 1 / k B = − 19.54 K and J 2 / k B = 27.55 K), showing the absence of interchain dimerization of the Co ions. This indicates that the "dimer+monomer" model used for Ni 2 V 2 O 7 [Cao et al., Phys. Rev. B 106, 184409 (2022)] is no longer applicable to Co 2 V 2 O 7. Finally, the exact diagonalization of spin Hamiltonian, including anisotropic exchanges, produces the experimentally observed 1/2 and 3/4 magnetization plateaus. [ABSTRACT FROM AUTHOR]

In magnetic tunnel junctions (MTJs), an antiferromagnetic iridium manganese (IrMn) layer neighboring a ferromagnetic electrode is indispensable for pinning the magnetization of the ferromagnet. The effect of its antiferromagnetism on adjacent ferromagnet and, thus, the quantum transport is, nevertheless, scarcely studied. Here, we investigate the role of antiferromagnetically orientated Mn spins in IrMn on the spin-dependent tunneling transport in IrMn/FeCo/MgO/FeCo/IrMn MTJ by analyzing the tunneling magnetoresistance (TMR) effect. The opposite spin orientation of Mn induces the mixing of Bloch symmetries, Δ 1 and Δ 5 , irrespective of the spin alignment of the FeCo electrode. This auxiliary contribution from the Mn spins improves the tunneling in majority- and minority-spin channels in parallel configuration. In the antiparallel configuration, the tunneling in majority- and minority-spin channels is non-identical. The TMR as high as 8643% is obtained under equilibrium. In addition, the non-equilibrium behavior of TMR and the spin-filtering effect are examined in the voltage bias range of 10–50 mV. The TMR ratio of 3600% with the spin-filtering efficiency of ∼ 98% is maintained at 50 mV, presenting the MTJ as an effective spin-filtering device robust to the bias endurance. Finally, it is speculated that our device structure can be a potential spin–orbit torque-based MTJ that offers a giant TMR and promotes upscaling of the generation of multi-bit devices with a simplified design strategy. [ABSTRACT FROM AUTHOR]

Understanding the internal magnetization structure of an individual ferromagnetic nanoparticle (MNP) is crucial for deciphering its magnetic characteristics. Unfortunately, while certain techniques can measure the magnetic properties of an individual MNP, they fall short of accurately detecting the internal magnetization structure. In this work, micromagnetic simulations were employed to construct the internal magnetization structure of an individual CoFe2O4 (CFO) nanopyramid, and the energy jump behavior during the magnetization process was successfully explained, with simulation results aligning with dynamic cantilever magnetometry (DCM) experimental outcomes. Subsequently, the external stray field of the nanopyramid was simulated, and the stray field gradient map revealed distinct bright and dark regions corresponding to the reverse and forward saturation magnetizations of the CFO nanopyramid. This result is possible to be verified by magnetic force microscopy (MFM) measurements of individual CFO nanopyramids. The confidence in the accuracy of the simulated internal magnetization structure was significantly enhanced by independently verifying the micromagnetic simulation results through DCM and MFM experiments. Our work proposes a convenient and cost-effective method for studying the internal magnetization structure of individual MNPs. [ABSTRACT FROM AUTHOR]

We investigated the magnetic properties of Sendust (Fe-Al-Si) alloys not only at 0 K but also at finite temperatures by means of the first-principles calculations assuming A2, B2, and D 0 3 structures. We confirmed that the itinerant characteristics of 3 d electrons of Fe are not negligible and a significantly small exchange stiffness constant exists at zero temperature in a B2 structure. However, the calculated Curie temperatures are in the same order for all structures; this indicates that the Curie temperature cannot be determined only by the exchange interactions at zero temperature in itinerant electron systems. Temperature dependence of the exchange interaction, namely, spin configuration dependence, also might be important for determining it. In addition, this property might also be related to the unique behavior of the temperature dependence of the exchange stiffness constant for the B2 structure, which does not decrease monotonically as temperatures increase, contrary to the behavior expected from the Heisenberg model. In addition, we investigated composition dependence on the exchange stiffness constant at zero temperature and confirmed that the substitution of Si with Al could improve the amplitude of the exchange stiffness constant at zero temperature for all structures. [ABSTRACT FROM AUTHOR]

The development and technological applications of molecular spin systems require versatile experimental techniques to characterize and control their static and dynamic magnetic properties. In the latter case, bulk spectroscopic and magnetometric techniques, such as AC magnetometry and pulsed electron paramagnetic resonance, are usually employed, showing high sensitivity, wide dynamic range, and flexibility. They are based on creating a nonequilibrium state either by changing the magnetic field or by applying resonant microwave radiation. Another possible source of perturbation is a laser pulse that rapidly heats the sample. This approach has proven to be one of the most useful techniques for studying the kinetics and mechanism of chemical and biochemical reactions. Inspired by these works, we propose an inductive detection of temperature-induced magnetization dynamics as applied to the study of molecular spin systems and describe the general design and construction of a particular induction probehead, taking into account the constraints imposed by the cryostat and electromagnet. To evaluate the performance, several coordination compounds of VO2+, Co2+, and Dy3+ were investigated using low-energy pulses of a terahertz free electron laser of the Novosibirsk free electron laser facility as a heat source. All measured magnetization dynamics were qualitatively or quantitatively described using a proposed basic theoretical model and compared with the data obtained by alternating current magnetometry. Based on the results of the research, the possible scope of applications of inductive detection and its advantages and disadvantages in comparison with standard methods are discussed. [ABSTRACT FROM AUTHOR]

Programmable and non-volatile spin-based logic devices have attracted significant interest for use in logic circuits. Realization of logic operations via spin–orbit torque (SOT) driven magnetization switching could be a crucial step in the direction of building logic-in-memory architectures. In this work, we demonstrate experimentally, the realization of four logic operations in a heavy metal/ferrimagnet bilayer structure via SOT switching. We also propose a general scheme for choosing input parameters to achieve programmable logic operations. The bulk and tunable perpendicular magnetic anisotropy and relatively lower saturation magnetization in ferrimagnets are found to make them more energy efficient in performing logic operations, as compared to conventional ferromagnets. Thus, ferrimagnets are promising candidates for use in logic-in-memory architectures, leading to the realization of user-friendly spin logic devices in the future. [ABSTRACT FROM AUTHOR]

This paper reports on the application of a near-infrared (NIR) imaging system for visualizing heat transfer dynamics from a bulk gadolinium (Gd) sample to the surrounding water during the magnetization/demagnetization process of the magnetocaloric effect (MCE). The suggested approach relied on the spectral variation in water absorption band at 1150 nm wavelength within the NIR spectrum. An experimental setup integrated a telecentric uniform-illumination system, a halogen lamp, and an NIR camera to enable real-time monitoring of a single magnetization and demagnetization cycle induced by an external magnetic field, which was generated by a permanent-magnet-based magnetic circuit. Two-dimensional absorbance images captured during this cycle clearly depicted the thermal energy generated by the MCE in water. Furthermore, an analysis of the thermal boundary layer and the quantification of heat transfer from Gd to water provided insights into the dynamics over time. These results indicated the potential of our NIR imaging techniques in optimizing thermal–fluid interactions within MCE systems, thereby improving the design and efficiency of magnetic refrigeration systems. [ABSTRACT FROM AUTHOR]

The anomalous-Hall current injection is studied in a Hall device contacted to a lateral load circuit. This anomalous-Hall current is generated inside a Co 75 Gd 25 ferrimagnetic Hall bar and injected into a lateral load circuit contacted at the edges. The current, the voltage, and the power are measured as a function of the magnetization states, the load resistance R l , and the temperature. It is shown that (1) the resistance associated with the anomalous-Hall current flowing inside the Hall bar is that of the portion of the ferrimagnet located between the lateral contacts, (2) the role of the non-uniformity of the current due to the lateral contacts is small, (3) the maximum power efficiency of the current injection into the load circuit corresponds to the condition of the resistance matching of the two sub-circuits, and (4) this maximum power efficiency is of the order of the square of the anomalous-Hall angle. These observations are in agreement with recent predictions based on a non-equilibrium variational approach. [ABSTRACT FROM AUTHOR]

We investigate the impact of non-collinear dual optical excitation on magnetization precession in a permalloy thin film using two ultrashort laser pulses. By analyzing the magnetization dynamics using time-resolved magneto-optical methods, we find that excitation with two ultrashort optical pulses introduces a long-lasting modification of the electron system, as indicated by a sizable decrease in the precession frequency and a significant increase (approximately 25%) in the decay time. Our results reveal that the observed effect strongly depends on the respective polarizations of the two excitation pulses and the time delay between the two optical pulses. Our findings indicate the occurrence of a nonlinear opto-spin effect during photoexcitation with two interfering optical pulses, which can potentially be observed in various materials and at different photon wavelengths. [ABSTRACT FROM AUTHOR]

Writing and reading of magnetization states via mechanical strain are crucial for the development of ultralow-power spintronic devices. In this study, a van der Waals magnetic tunnel junction (vdW MTJ) of Fe3GaTe2/h-BN/MnBi2Te4 is constructed to explore the magnetization reversal under in-plane biaxial strains. Interestingly, the interlayer magnetic coupling of devices can be tuned to ferromagnetic and antiferromagnetic states by tensile and compressive strains, respectively. The various magnetic couplings on applied strains are analyzed using the superexchange theory. Importantly, the interlayer coupling nearly vanishes after removing external strains, ensuring the nonvolatility of magnetization reversal, resulting in the nonvolatile writing of magnetization states in the present vdW MTJ. Moreover, the tunneling magnetoresistance ratio of the device is up to −5745%, which remains −1478% even with −2% strain, showing great potential for reading the magnetization states. Therefore, this work provides an alternate avenue to write and read magnetization states in one vdW MTJ under biaxial strains. [ABSTRACT FROM AUTHOR]

We have fabricated the ZnFe2O4/ZnO (ZFO/ZnO) heterostructure on a silicon substrate by pulsed laser deposition technique and studied the magnetization switching by the electric field in the ZFO/ZnO heterostructure using an indigenously developed optical cantilever beam magnetometer setup. The magnetization (M) vs electric field (E) curve reveals that the magnetization of the ZFO film has been switched by an electric field applied along the thickness of the ZnO film. The saturation magnetization is found to be 28.77 MA/m from the M–E curve. The emergence of electric field-driven magnetization switching in the ZFO/ZnO heterostructure is attributed to the strain-mediated magnetoelectric coupling between the electric polarization of the ZnO film and the magnetization of the ZFO film as evidenced by the butterfly-type hysteresis behavior of magnetization with the applied electric field. However, the realization of electric field-controlled magnetization switching in the ZFO/ZnO heterostructure is regarded as a potential aspect for the fabrication of energy-efficient spintronic devices such as magnetoelectric random access memory cells, highly sensitive magnetic field sensors, magneto-logic devices, and neuromorphic devices. [ABSTRACT FROM AUTHOR]

Alloying heavy metals (HMs) has been an effective method for enhancing the efficiency of spin–orbit torque. In this study, we demonstrate that Pt100−xWx/Pt/Co/Ta multilayers still maintain perpendicular magnetic anisotropy after high-temperature annealing. Doping tungsten (W) into HM platinum (Pt) at the bottom of a Pt/Co/Ta multilayer significantly increases the spin Hall angle (θ S H ) and reduces the critical switching current density (Jc). The harmonic Hall test results show that the θ S H of the Pt88W12 alloy film is approximately 0.29, which is higher than that of the pure Pt film (0.15). The magnetization switching test reveals that the Jc of Pt94W6 alloy film is approximately 4.892 × 106 A/cm2, which is 51.9% lower than that of the pure Pt film. This study offers a valuable method for reducing power consumption and enhancing the efficiency of related application devices. [ABSTRACT FROM AUTHOR]

This study explores how magnetization manipulation occurs in a flowing medium over a pipe geometry using nuclear magnetic resonance methods. In particular, the experimental conditions on radio frequency pulsing and the signal detection are studied in an ultra-low frequency regime of a few kilohertz. An analytical model of the magnetization preparation is presented, which calculates the magnetization distribution of an excited flowing segment. The effective flip angle distribution is mapped to simulate the temporal development of the magnetization in the segment. The simulation results are compared to the experimental data from a flow metering setup. As a result, the quantitative impact of the flow profile on the magnetic signal is shown. [ABSTRACT FROM AUTHOR]

We report an enhanced magnetoelectric (ME) effect in spin–phonon coupled single-phase La1−xSmxYFe2O6 (0 ≤ x ≤ 1). The structural, electric, magnetic, and ME properties have been investigated to establish their interplay leading to magnetoelectricity. X-ray diffraction study suggests the facilitation of the P21nm phase (double perovskite lattice arrangements) formation and improved structural order due to the substitution of Sm in the lattice. Antiferromagnetic (AFM) transition ∼700 K along with a spin-reorientation transition around room temperature (RT) and below is observed in the thermomagnetic curve. The indication of short range ordering in the magnetization data in the form of a non-Griffiths-like phase (nGP) is observed. The short range ordering could be minimized along with consequent improvement in AFM ordering, due to Sm substitution. An enhanced (∼31% with respect to x = 0) RT first-order ME coupling coefficient ∼0.59 mV cm−1 Oe−1 in x = 0.75 composition is observed. The findings reported here open the door to exercise spin-reorientation transition in the spin–phonon coupled double perovskites for spintronic device applications. [ABSTRACT FROM AUTHOR]

We have investigated the magnetization reversal processes and dynamic behavior of trilayered Py(50 nm)/Pd(tPd)/Py(20 nm) nanowires with periodic width modulation as a function of spacer layer thickness tPd in the range from 0 to 10 nm and compared them with single-layer nanowires. The ferromagnetic resonance spectra show more than three modes that result from a non-uniform demagnetizing field in width-modulated nanowires. We observe that the spacer layer thickness influenced the ferromagnetic resonance spectra, which showed different numbers and values of modes and frequencies due to the different magnetization configurations for different spacer layer thicknesses. We also found that the two ferromagnetic layers are exchange-coupled for tPd = 2 nm nanowire arrays, showing the sharp switching of magnetization from the static measurements and sharp frequency jump from 13.6 to 14.7 GHz around −18 mT from the dynamic measurements. However, for tPd = 10 nm, the two layers switch at different fields, indicating a gradual decrease in magnetization as the reversal is mediated through dipolar coupling. The origin of modes is well explained from the spatial mode profiles of top and bottom magnetic layers. The dynamic responses in this spin-valve-type structure are useful for designing microwave-based spintronic devices. [ABSTRACT FROM AUTHOR]

We report an enhanced magnetoelectric (ME) effect in spin–phonon coupled single-phase La1−xSmxYFe2O6 (0 ≤ x ≤ 1). The structural, electric, magnetic, and ME properties have been investigated to establish their interplay leading to magnetoelectricity. X-ray diffraction study suggests the facilitation of the P21nm phase (double perovskite lattice arrangements) formation and improved structural order due to the substitution of Sm in the lattice. Antiferromagnetic (AFM) transition ∼700 K along with a spin-reorientation transition around room temperature (RT) and below is observed in the thermomagnetic curve. The indication of short range ordering in the magnetization data in the form of a non-Griffiths-like phase (nGP) is observed. The short range ordering could be minimized along with consequent improvement in AFM ordering, due to Sm substitution. An enhanced (∼31% with respect to x = 0) RT first-order ME coupling coefficient ∼0.59 mV cm−1 Oe−1 in x = 0.75 composition is observed. The findings reported here open the door to exercise spin-reorientation transition in the spin–phonon coupled double perovskites for spintronic device applications. [ABSTRACT FROM AUTHOR]

Spin–orbit torque (SOT) can provide efficient electrical manipulation of magnetism via applying electrical current to breaking the symmetry of damping-like torque. In the heterojunction of heavy and ferromagnetic metal, Dzyaloshinskii–Moriya interaction (DMI) is one of the key ingredients for stabilizing chiral spin structures, like chiral domain walls. Meanwhile, materials with larger charge-spin conversion rates are also highly expected for the efficient SOT. In this paper, spin–orbit torque magnetic switching is observed in the perpendicularly magnetized Pt/Co/Bi2Se3 and shows relatively high efficiency with low critical switching current density of about 5 × 105 A cm−2. The SOT efficiency and DMI in perpendicularly magnetized Pt/Co/Bi2Se3 were quantitatively investigated by electrical detection of the effective spin Hall field. The DMI constant is about 2.6 mJ m−2, and the effective spin Hall angle of Pt/Co/Bi2Se3 is about 0.14. The work also demonstrates that the Bi2Se3 layer takes the main responsibility for SOT, and the Pt/Co interface is the main source of DMI in Pt/Co/Bi2Se3 structures, which makes it possible to achieve independent optimization of DMI and SOT in the Pt/Co/Bi2Se3 structure at room temperature for the advanced application of spintronic devices. [ABSTRACT FROM AUTHOR]

We investigated the field-dependent Néel relaxation time of magnetic nanoparticles (MNPs) in an AC excitation field. Specifically, a fundamental component of the magnetization for immobilized MNPs was studied by numerical simulation while changing the frequency f and amplitude Hac of the field. From the simulation results, we clarified the Hac dependence of the effective Néel relaxation time τN,e and obtained an empirical expression for τN,e(Hac) for the first time. The expression was obtained for the cases when the angle of the easy axis of magnetization in MNPs is fixed and randomly distributed. Using the Hac dependencies of τN,e and the previously reported Brownian relaxation time τB,e, we showed that the behavior of suspended MNPs changes from Brownian-dominant to Néel-dominant when Hac increases, even when the MNP parameters are fixed, and we obtained an expression for the boundary field between them. Furthermore, we classified several types of responses for the suspended MNPs in the AC field using the magnitude relationship among τN,e(Hac), τB,e(Hac), and 1/(2πf). Finally, we experimentally verified the classification, and reasonable agreement was observed between the experiment and analysis. The results are useful for determining suitable MNP parameters and excitation conditions for various biomedical applications. [ABSTRACT FROM AUTHOR]

Nutation and precession resonances in an antiferromagnet subjected to a dc magnetic field are investigated by employing coupled linearized inertial Landau–Lifshitz–Gilbert equations describing the dynamics of magnetizations of antiferromagnet sublattices with uniaxial magnetocrystalline anisotropy. Analytical expressions for the eigenfrequencies of such an antiferromagnet are obtained for the longitudinal and transverse directions of the external dc field and for different ranges of its strength. The effect of inertia on the values of the resonant frequencies is shown for all possible states of the antiferromagnet in both the longitudinal and transverse directions of the external field. The estimated resonant frequencies are compared with those obtained from the numerical solution of the system of undamped inertial Landau–Lifshitz–Gilbert equations for closed trajectories of sublattice magnetizations. The good agreement of both independent estimations is demonstrated. [ABSTRACT FROM AUTHOR]

Spin–orbit torque (SOT) can provide efficient electrical manipulation of magnetism via applying electrical current to breaking the symmetry of damping-like torque. In the heterojunction of heavy and ferromagnetic metal, Dzyaloshinskii–Moriya interaction (DMI) is one of the key ingredients for stabilizing chiral spin structures, like chiral domain walls. Meanwhile, materials with larger charge-spin conversion rates are also highly expected for the efficient SOT. In this paper, spin–orbit torque magnetic switching is observed in the perpendicularly magnetized Pt/Co/Bi2Se3 and shows relatively high efficiency with low critical switching current density of about 5 × 105 A cm−2. The SOT efficiency and DMI in perpendicularly magnetized Pt/Co/Bi2Se3 were quantitatively investigated by electrical detection of the effective spin Hall field. The DMI constant is about 2.6 mJ m−2, and the effective spin Hall angle of Pt/Co/Bi2Se3 is about 0.14. The work also demonstrates that the Bi2Se3 layer takes the main responsibility for SOT, and the Pt/Co interface is the main source of DMI in Pt/Co/Bi2Se3 structures, which makes it possible to achieve independent optimization of DMI and SOT in the Pt/Co/Bi2Se3 structure at room temperature for the advanced application of spintronic devices. [ABSTRACT FROM AUTHOR]

Spin–orbit torque provides an efficient strategy for electric manipulation of magnetization. However, Joule heat accompanying with electron motion in the electron-mediated spin current result in unavoidable power dissipation. Moreover, the spin diffusion length in electron-mediated spin current is relatively short, preventing the transmission of spin information over long distances. Magnon-mediated spin current, without moving electrons, can be an excellent alternative to the conventional spin current. Magnon-mediated transfer torque effect has been reported in several previous works. Here, we report the magnon-mediated spin Hall magnetoresistance (SMR) and unidirectional magnetoresistance (UMR) in Pt/NiO/NiFe structures. The significant SMR and UMR were observed in the samples with the NiO thickness up to 60 nm, demonstrating the efficient transmission of magnon-mediated spin current over long distances in the NiO layer. In addition, we observed current-induced in-plane magnetization switching in the NiFe layer via the UMR measurement. These results demonstrated the possibility for developing the efficient spintronic devices operated by magnons. [ABSTRACT FROM AUTHOR]

We investigate the magnetization and the Dzyaloshinskii–Moriya interactions (DMI) in Pt/Co/Re thin films in the case of perfect interfaces and upon the introduction of intermixing on both Co interfaces. Calculations were implemented on a series of systems with a countable number of cobalt atomic layers. Remarkably, Re can introduce a DMI at the interface with cobalt and also increase the DMI at the Pt/Co interface. We demonstrate that the chiral magnetic multilayer Pt/Co/Re with a chiral spin structure can achieve a substantial DMI value, which is almost double that attained in the prototype system Pt/Co/W. We also study the DMI as a function of the Re thickness, finding the optimal thickness to maximize the DMI. When we include a disorder that cancels a contribution from all first-neighbor Co atoms in the intermixed region, we find out that intermixing at the two interfaces affects the strength of the DMI solely when introduced at the Pt/Co interface, where the DMI loses almost half of its value. On the contrary, the mixing at the Co/Re interface has very little or no effect where the calculated values were not significantly decreased as compared to the case with perfect interfaces. [ABSTRACT FROM AUTHOR]

Many natural substances in nature exhibit magnetism, which has a significant impact on human life. However, accurately predicting, analyzing, and manipulating magnetic fields requires the use of precise mathematical simulation techniques. One such method is numerical modeling with element matrices, which is crucial for simulating and analyzing complex physical models. In conventional mesh-based modeling, there is always a residual error, and the accuracy of the solution can be greatly affected by the mesh density. This work proposed a new numerical modeling theory for the field of magnetics, which is based on specially designed points within an element. With this new computational framework, the mesh-dependence feature of the element matrix can be significantly reduced, allowing for more efficient convergence to the theoretical value with minimal differences. This method can handle a wide range of extreme physical conditions in both three-dimensional and two-dimensional scenarios, which are beyond the capabilities of conventional methods, and can provide highly accurate computational solutions. The proposed method is demonstrated through the passive shielding design of a 9.4 T whole-body magnetic resonance imaging superconducting magnet, and the concept design of an extremely weak magnetic field scientific facility with cross-scale geometry was exemplified by the proposed method. [ABSTRACT FROM AUTHOR]

Spintronic terahertz (THz) emitters have been shown to be a cost-efficient source for use in time-domain THz spectroscopy. The use of external magnetic fields to control the polarity of the THz emission provides an opportunity to measure the magnetization of spintronic materials as well as shaping THz emission. Here, we demonstrate an efficient method of measuring magnetic hysteresis with material sensitivity and speed several orders of magnitude greater than typical magnetometry methods. In addition, we utilize the rapid control of material magnetization for lock-in detection in time-domain THz spectroscopy of spintronic emitters. The ability to rapidly control and measure the material magnetization on very small volumes provides an opportunity to study magnetic hetero-structures with sub-micron spatial resolution. [ABSTRACT FROM AUTHOR]

This study shows that magnetic linear dichroism (MLD) measurement has great potential for characterizing magnetic nanoparticles (MNPs) used in recently developing biomedical applications or nanoscale mechanical measurement techniques. MLD of MNP suspension reflects the orientation of the MNP. We investigated the frequency dependence of the MLD of MNP suspension under a simple AC field and the effect of the MNP size and material. Under an AC field with the frequency f, the MLD oscillated with 2f for every MNP. The amplitude and phase of this 2f-oscillation were precisely measured with a lock-in amplifier, and we showed the MLD2f frequency spectrum, a plot of real and imaginary parts of the 2f-component of MLD as a function of f. We found that the shape of the MLD2f frequency spectrum can distinguish the rotational modes of MNPs in an AC field. Therefore, this spectrum is helpful for the selection of MNPs for each technique mentioned above. We propose two model functions to fit the MLD2f frequency spectra, consistent with each rotational mode. It is shown that one of the fitting parameters τ0 is associated with the rotational Brownian relaxation time of MNP, and the other parameter β would represent the distribution of the anisotropy energy. The frequency dependence of MLD will provide precise insights into the magnetization and orientational dynamics of the MNP in liquid. [ABSTRACT FROM AUTHOR]

Using a molecular beam epitaxy technique, we experimentally demonstrate a multiferroic heterostructure consisting of metastable ferromagnetic Co 3 Mn on piezoelectric Pb(Mg 1 / 3 Nb 2 / 3 )O 3 –PbTiO 3 (PMN-PT). Inserting a 2-nm-thick Fe layer between Co 3 Mn and PMN-PT(001) allows the formation of bcc Co 3 Mn layers even at an extremely low growth temperature of ∼ 80 ° C. Upon increasing this temperature to 200 ° C, a bcc Co 3 Mn/Fe/PMN-PT(001) multiferroic heterostructure with a relatively large saturation magnetization of ∼ 1680 kA/m and an atomically flat interface is obtained, resulting in an obvious converse magnetoelectric (CME) effect. The large CME effect originates mainly from the strain-induced modulation of the magnetic anisotropy energy, supported by the first-principles calculations. [ABSTRACT FROM AUTHOR]

We demonstrate experimentally and numerically the control of magnetization circulation of the closure domain state in thin permalloy squares divided diagonally into four dipolar-coupled isosceles triangles. The control over the magnetization circulation was achieved by the mutual application of a suitable external in-plane magnetic field and interaction with a magnetic force microscopy (MFM) tip. Numerical simulations confirm that the proposed switching protocol is valid for the broad range of MFM tips. Experiments performed on four diagonally cut squares show that this method is robust against slight imperfections in the fabrication process. Moreover, by varying the polarity of the applied field and the direction of the MFM scanning, proper symmetry response of the switching method is observed. [ABSTRACT FROM AUTHOR]

This Tutorial article focuses on magnetic phenomena and material systems that have gained significant importance since the original development of mumax3, but are challenging to simulate for users who rely solely on the originally provided examples. Alongside the physical background, we provide hands-on examples of advanced magnetic systems, including detailed explanations of complete mumax3 input files (13 in total, often showing different ways to achieve things), and highlighting potential pitfalls where applicable. Specifically, we explore two approaches to incorporate spin–orbit torques in mumax simulations, considering the trade-off between versatility and speed. We also examine complex multilayer material stacks, including synthetic antiferromagnets, demonstrating different implementation methods that again vary in speed, versatility, and realism. A key criterion for selecting the optimal simulation strategy is its suitability for modeling systems where the magnetization varies significantly in the third dimension. The material covered in this Tutorial paper includes content developed for the mumax3 workshop presented during the summer of 2020 within the context of the IEEE online spintronics seminar, along with additional new topics. Throughout the explanations, we ensure broad applicability beyond specific examples. [ABSTRACT FROM AUTHOR]

We numerically demonstrate that a pure time-harmonic bias AC current of a specific amplitude τ f and angular frequency ω f can excite the chaotic magnetization dynamics in a Josephson-like antiferromagnetic (AFM) spin Hall oscillator (SHO) with biaxial magnetic anisotropy of an AFM layer. The nature of such a stochastic generation regime in a Josephson-like AFM SHO could be explained by the random hopping of the working point of the SHO between several quasi-stable states under the action of an applied AC current. We reveal that depending on the ω f / τ f ratio several stochastic generation regimes interspersed with regular generation regimes can be achieved in an AFM SHO, which can be used in spintronic random signal sources and various nano-scale random signal devices, including the spintronic p-bit device considered in this work. The obtained results are important for the development and optimization of spintronic devices capable of generating and processing (sub-)THz-frequency random signals, which are promising for ultra-fast probabilistic computing, cryptography, secure communication, etc. [ABSTRACT FROM AUTHOR]

A polycrystalline ZnO film is grown on a silicon substrate by the pulsed laser deposition method, and the electric field-induced magnetization in ZnO using an optical cantilever beam magnetometer setup is studied. The magnetization vs bipolar dc electric field measurements reveal the occurrence of magnetization switching in the ZnO film. The magnetization switching in the presence of an electric field is ascribed to the converse magnetoelectric (ME) coupling that takes place between the electrical and the magnetic order parameters existing in the ZnO film. We have found the strain-driven magnetization change as evidenced by the butterfly shape of the magnetization vs the electric field curve. A saturation magnetization of 13.31 MA/m is obtained. Moreover, a significant value of the ME coupling coefficient (α) (1.61 × 10−7 s/m) has also been reported in this article. The emergence of electric field-induced magnetization in a single polycrystalline ZnO film is regarded to be a very promising aspect in designing high-density energy-efficient spintronic and different multifunctional devices. [ABSTRACT FROM AUTHOR]

We have conducted the study of structural, magnetic, magnetothermal, and magnetoelastic properties of four rare-earth compounds: Gd4.5Tb0.5Si2Ge2, Gd4TbSi2Ge2, Gd4.4Tb0.5Ti0.1Si2Ge2, and Gd3.9TbTi0.1Si2Ge2 in the vicinity of magnetically induced phase transitions. We demonstrate that the introduction of Ti into the rare-earth sublattice separates the structural and magnetic phase transitions and changes the order of magnetic phase transition from type I to II, while preserving high values of magnetocaloric effect (MCE). Additionally, incorporating a small quantity of Tb enables the creation of compounds with enhanced MCE values over a specific temperature range of 240–290 K. The observed phenomena can be attributed to the combined effects of forced magnetization and alteration of magnetic susceptibility during the structural phase transition that accompany the magnetic phase changes in these compounds. [ABSTRACT FROM AUTHOR]

We demonstrate the possibility of a coupling between the magnetization direction of a ferromagnet and the tilting angle of adsorbed achiral molecules. To illustrate the mechanism of the coupling, we analyze a minimal Stoner model that includes Rashba spin–orbit coupling due to the electric field on the surface of the ferromagnet. The proposed mechanism allows us to study magnetic anisotropy of the system with an extended Stoner–Wohlfarth model and argue that adsorbed achiral molecules can change magnetocrystalline anisotropy of the substrate. Our research aims to motivate further experimental studies of the current-free chirality induced spin selectivity effect involving both enantiomers. [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) trapped field magnets can generate and maintain stable, high magnetic fields without requiring external power supplies. Recently, HTS-stacked ring magnets have garnered significant attention due to their flexible geometry, robust mechanical strength, and proven trapped field performance. In this study, we examine the magnetization characteristics of HTS-stacked ring magnets and observed a trapped field higher than the applied field during field cooling magnetization. We also observed that by inserting HTS stacks into the hollow cavity of the HTS-stacked rings, the center field ceased to exhibit an increased center field. Our analysis revealed that the unique induced current distribution and the penetration sequence are the underlying causes. Inspired by the investigation results, we explored deeper into the magnetization properties and identified that a final trapped field higher than the applied field can be achieved through proper design and magnetization of the HTS-stacked ring magnets. However, even though the trapped central field experiences an increase, this does not translate into an increment in the total trapped flux. Instead, a redistribution of the flux is observed. These findings hold significant implications for the design and application of superconducting magnets. [ABSTRACT FROM AUTHOR]

Many exciting effects resulting from the coupling of magnetic sublattice with a magnetic field, may be exposed by changing the field. One such phenomenon is the magnetocaloric effect, which is characterized by the absorption or emission of heat in response to changes in the external magnetic field. Magnetic refrigeration based on the magnetocaloric effect has emerged as an attractive alternative to conventional cooling technology that relies on gas compression and expansion. It is not only more efficient and environmentally friendly, but it can also be implemented across a broad temperature range, from ultra-low to a few hundred Kelvin temperatures. One of the areas where magnetic cooling can have a significant impact is hydrogen liquefaction. Hydrogen is one of the most promising candidates for clean energy sources, but it must be liquefied to facilitate storage and transportation, which requires cooling it down to ∼20 K. The ideal magnetic refrigerant should exhibit consistent magnetocaloric properties across the entire operating temperature range of a cooler. This paper presents novel three-layer composite magnetic refrigerants that provide a uniform magnetocaloric response over a 30 K temperature range. The selected initial HoNi 2 , DyNi 2 , and TbNi 2 magnetic intermetallic compounds with a Laves phase structure exhibit large magnetocaloric properties in the temperature range of 13–37 K. The composite composition of 23.56 wt% HoNi 2 + 18.21 wt% DyNi 2 + 58.23 wt% TbNi 2 optimized for 2 T magnetic field change, was determined through numerical approach. The composites are manufactured using spark plasma sintering (SPS) and innovative high-isostatic-pressure (HIP) synthesis. The results of isothermal entropy change derived from magnetization data for a 2 T magnetic field change indicated 4.7 J/kgK (47.2 mJ/cm3K) and 4.4 J/kgK (44.2 mJ/cm3K) in the temperature range of approx. 13–42 K for composites after SPS and SPS + HIP processes, respectively. Despite the sample subjected to HIP showing slightly lower results, the entropy change is nearly uniform over the 30 K temperature range due to enhanced atomic diffusion between neighboring compounds, as confirmed by microscopic studies. Such a uniform magnetocaloric response in ∼30-K temperature range has never been observed before in layered refrigerants. By utilizing the innovative high-isostatic-pressure synthesis technique, we have paved the way to high-performing magnetic composite materials that can be used in cryogenic magnetic coolers operating over a broad temperature span, expanding the possibilities of what can be achieved and laying the foundation for cost-effective, clean hydrogen energy. [Display omitted] • Layered HoNi2 + DyNi2 + TbNi2 composites are investigated. • Spark plasma sintering (SPS) and high-isostatic-pressure (HIP) synthesis are used. • Both SPS and SPS + HIP samples provide similar magnetic entropy changes over a 30 K. • HIP improves uniformity of magnetic entropy changes. [ABSTRACT FROM AUTHOR]

The triangular-type Ising nanowire is constructed on the Bethe lattice (BL) by using the core-shell structure consisting of spin-3/2 atoms as the core and spin-1/2 atoms as the triangular shell. Each triangular plaquette of spins forms a nanoparticle which is connected to upper and lower plaquettes symmetrically. The additions of the plaquettes continue indefinitely until the thermodynamic limit to construct the nanowire. The inter- and intra-bilinear interaction parameters (J) are assumed to be positive or negative to simulate the ferromagnetic (FM) or antiferromagnetic (AFM) interactions, respectively. The crystal field for spin-3/2 and external magnetic field for all sites are also included into the model. After obtaining the formulation of the model in terms of exact recursion relations (ERRs), the thermal variations of magnetizations are studied in detail to obtain the phase diagrams. It is found that the model leads to different types of FM and AFM regions with various forms of phase transitions. It is also interesting that the model presents random or oscillatory magnetization behavior regions for the appropriate values of our system parameters. [ABSTRACT FROM AUTHOR]

Spin–orbit torque (SOT)-based perpendicularly magnetized memory devices with multistate memory have garnered significant interest due to their applicability in low-power in-memory analog computing. However, current methods are hindered by initialization problems, such as prolonged writing duration, and limitations, on the number of magnetic states. Consequently, a universal method for achieving multistate in perpendicular magnetic anisotropy (PMA)-based stacks remains elusive. Here, we propose a general experimental method for achieving multistate without any initialization step in SOT-driven magnetization switching by integrating an external out-of-plane magnetic field. Motivated by macrospin calculations coupled with micromagnetic simulations, which demonstrate the plausibility of magnetization state changes due to out-of-plane field integration, we experimentally verify multistate behavior in Pt/Co/Pt and W/Pt/Co/AlOx stacks. The occurrence of multistate behavior is attributed to intermediate domain states with Néel domain walls. We achieve repeatable 18 multistate configurations with a minimal reduction in retentivity through energy barrier measurements, paving the way for efficient analog computing. [ABSTRACT FROM AUTHOR]

Analyzing the magnetization reversal process is crucial for enhancing the magnetic properties of nanocomposite magnets, thereby subsequently increasing the magnetic energy product and advancing the development of next-generation rare earth permanent magnet materials. Here, the open recoil loop is systematically investigated based on micromagnetic simulations and comparing magnetization configurations, which is strongly associated with the asymmetric behavior of weak pinning at the soft/hard magnetic interface. By removing and reapplying field, the irreversible weak pinning sites exhibit asymmetric behavior, leading to the formation of open phenomena in nanocomposites. The open degree of recoil loops obtained from experimental testing was also correlated with the irreversible magnetization, which supports the simulation results. Our findings provide a novel approach for understanding the magnetization reversal mechanism in nanocomposite magnets. [ABSTRACT FROM AUTHOR]

For the first time, the magnetic and optical (bandgap) properties of co‐doped Mg/Dy, Al/Dy, and Mn/Nd SrFe12O19$\left(\text{SrFe}\right)_{12} \left(\text{O}\right)_{19}$ (SFO) at Sr and Fe sites are investigated using a microscopic model and the Green's function theory. It is shown that the co‐doping at both Sr and Fe sites can change the behavior of the magnetization which decreases by transition metal or nonmagnetic ion doping at the Fe site (with doping ions larger than the host Fe ions), but by additive co‐doping at the Sr site with rare‐earth ion (which ionic radius is smaller than that of Sr) the magnetization increases with increasing the co‐doping concentration. The bandgap energy decreases in the co‐doped SFO. The mechanism of this co‐doping effect is explained on microscopic level. It is due to the changes of the spin‐exchange interaction constants at the doped sites caused by the appearance of different strain by the doping with two ions. The theoretical results are compared with the existing experimental data and are in good qualitative agreement. [ABSTRACT FROM AUTHOR]

In the present report, an unusual observation of Griffiths phase-like magnetic behavior in a geometrically frustrated antiferromagnetic system, Sr2InRuO6, has been discussed. This surprising magnetic behavior in the present sample is found to be associated with the presence of clusters above and below the critical temperature (Tcr ≈ 150 K). Two plausible scenarios are discussed for this intriguing observation of nonanalytical inverse susceptibility in this system. These scenarios are based on significant changes in the saturation magnetization of the clusters and changing concentrations of the clusters with decreasing temperatures. The average size of the clusters was estimated to be ∼4.9 nm at 300 K and ∼2.7 nm at 100 K. A ∼17-fold increase in the cluster concentration across Tcr ≈ 150 K results in non-analytical behavior of inverse susceptibility observed in this system. Additionally, the electrical properties of Sr2InRuO6 are reported. [ABSTRACT FROM AUTHOR]

In the present report, an unusual observation of Griffiths phase-like magnetic behavior in a geometrically frustrated antiferromagnetic system, Sr2InRuO6, has been discussed. This surprising magnetic behavior in the present sample is found to be associated with the presence of clusters above and below the critical temperature (Tcr ≈ 150 K). Two plausible scenarios are discussed for this intriguing observation of nonanalytical inverse susceptibility in this system. These scenarios are based on significant changes in the saturation magnetization of the clusters and changing concentrations of the clusters with decreasing temperatures. The average size of the clusters was estimated to be ∼4.9 nm at 300 K and ∼2.7 nm at 100 K. A ∼17-fold increase in the cluster concentration across Tcr ≈ 150 K results in non-analytical behavior of inverse susceptibility observed in this system. Additionally, the electrical properties of Sr2InRuO6 are reported. [ABSTRACT FROM AUTHOR]

The orbital Hall effect in light materials has attracted considerable attention for developing orbitronic devices. Here we investigate the orbital torque efficiency and demonstrate the switching of the perpendicularly magnetized materials through the orbital Hall material, i.e., Zr. The orbital torque efficiency of approximately 0.78 is achieved in the Zr orbital Hall material with the perpendicularly magnetized [Co/Pt]3 sample, which significantly surpasses that of the perpendicularly magnetized CoFeB/Gd/CoFeB sample (approximately 0.04). Such a notable difference is attributed to the different spin-orbit correlation strength between the [Co/Pt]3 sample and the CoFeB/Gd/CoFeB sample, confirmed through theoretical calculations. Furthermore, the full magnetization switching of the [Co/Pt]3 samples with a switching current density of approximately 2.6×106 A/cm2 has been realized through Zr, which even outperforms that of the W spin Hall material. Our finding provides a guideline to understand orbital torque efficiency and paves the way for developing energy-efficient orbitronic devices. Orbitronics opens an avenue for developing energy-efficient memory and logic devices through orbital Hall effect. Here, the authors realize the magnetization switching of perpendicularly magnetized materials through the orbital torque. [ABSTRACT FROM AUTHOR]

In this work, we prove the existence of time‐periodic solutions to a model describing a ferrofluid flow heated from below. Navier–Stokes equations satisfied by the fluid velocity are coupled to the temperature equation and the magnetostatic equation satisfied by the magnetic potential. The magnetization is assumed to be parallel to the magnetic field and is given by a nonlinear magnetization law generalizing the Langevin law. The proof is based on a semi‐Galerkin approximation and regularization methods together with the fixed point method. [ABSTRACT FROM AUTHOR]

This research paper delves into the enhancement of wastewater treatment through the design and synthesis of advanced photocatalytic materials, focusing on the effects of sodium (Na) substitution in Ca1‐xNaxTa0.5Ti0.5O3 perovskites. By employing various analytical techniques such as X‐ray diffraction, Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy and UV‐vis spectroscopy, the study examines the transition of these perovskites from tetragonal to orthorhombic structures and observes a reduction in Ca content with Na substitution, which also favors the cubic phase formation and inhibits secondary phases. Significantly, magnetic property analysis uncovers an unexpected ferromagnetic ordering in these perovskites, including compositions traditionally viewed as non‐magnetic. The photocatalytic tests reveal a significant improvement in degrading Rhodamine B dye under visible light, particularly in samples with higher Na levels, attributed to enhanced light absorption and efficient electron processes. The study highlights the optimal Na substitution level for peak photocatalytic performance, offering valuable insights into the complex interplay between structural, magnetic, and photocatalytic properties of these perovskites, and their potential in various applications, thereby contributing to the advancement of wastewater treatment technologies. [ABSTRACT FROM AUTHOR]

We study a variant of the Sherrington–Kirkpatrick (S–K) spin glass model with external field, where the random symmetric couplings matrix does not consist of i.i.d. entries but is instead orthogonally invariant in law. For sufficiently high temperature, we prove a replica-symmetric formula for the first-order limit of the model free energy. Our analysis is an adaptation of a conditional second-moment-method argument previously introduced by Bolthausen for studying the high-temperature regime of the S–K model, where one conditions on the iterates of an Approximate Message Passing (AMP) algorithm for solving the TAP equations for the model magnetization. We apply this method using a memory-free version of AMP that is tailored to the orthogonally invariant structure of the model couplings. [ABSTRACT FROM AUTHOR]

This study investigates the critical behavior analysis and predicting magnetocaloric properties of La0.6-xGdxSr0.4MnO3 manganites, focusing on the impact of varying gadolinium (Gd) doping levels (x = 0, 0.0125, 0.05, and 0.10). Using modified Arrott plots (MAPs) and the Kouvel–Fisher method, the critical exponents γ and β were determined, yielding values that indicate how Gd content influences magnetic phase transitions. Additionally, the magnetocaloric effect (MCE) was analyzed to assess the magnetic entropy change − Δ S M (T) and the Temperature-Averaged Entropy Change (TEC) across different magnetic field changes. The results show that increasing Gd doping enhances the magnetocaloric response, suggesting potential applications in magnetic refrigeration. Overall, the study provides insights into optimizing these manganites for applications in high-temperature sensors, spintronics, and magnetic cooling. Highlights: Using modified Arrott plots (MAPs) and the Kouvel–Fisher method, the critical exponents γ and β of La0.6-xGdxSr0.4MnO3 (x = 0, 0.0125, 0.05, and 0.10) manganites were derived. The magnetocaloric effect (MCE) was analyzed to assess the magnetic entropy change − Δ S M (T) and the Temperature-Averaged Entropy Change (TEC) across different magnetic field changes. [ABSTRACT FROM AUTHOR]

Rectangular magnetically shielded rooms (MSRs) are favored for their construction simplicity and efficient space usage. However, current rectangular MSRs lack an effective shielding factor (SF) theoretical system due to their inherent asymmetric geometry and process defects such as door gap. Therefore, an effective three-dimensional (3D) magnetic circuit method for calculating the SF of rectangular MSRs is proposed in this paper. Firstly, the theoretical model for the 3D magnetic circuit of rectangular MSRs is established, and the SF in three directions is derived. Secondly, the theoretical model is modified by introducing demagnetization factors to further improve the calculation accuracy of the SF based on the magnetization theory. Finally, formula systems for the SF considering door gap are derived, and their effect is also analyzed. To validate the proposed method, two rectangular MSRs with distinct structures are tested using a constructed experimental platform. The results show that the discrepancy between the calculated SF and the tested SF is less than 7%, affirming the efficacy of the proposed methodology. This method can be applied to rectangular MSRs of different sizes, and provide a valuable theoretical guidance for the construction of MSRs. [ABSTRACT FROM AUTHOR]

Magnetization dynamics, which determine the speed of magnetization switching and spin information propagation, play a central role in modern spintronics. Gaining its control will satisfy the different needs of various spintronic devices. In this work, we demonstrate that the surface oxidized Cu (CuOX) can be employed for the tunability of magnetization dynamics of ferromagnet/heavy metal (HM) bilayer system. The capping CuOX layer in CoFeB/W/CuOX trilayer reduces the magnetic damping value in comparison with the CoFeB/W bilayer. The magnetic damping even becomes lower than that of the CoFeB/CuOX by ∼ 16% inferring the stabilization of anti-damping phenomena. Further, the reduction in damping is accompanied by a very small reduction in the spin pumping-induced output DC voltage in the CoFeB/W/CuOX trilayer. The simultaneous observation of anti-damping and spin-to-charge current conversion could be attributed to the orbital Rashba effect observed at the HM/CuOX interface. Our experimental findings illustrate that the cost-effective CuOX can be employed as an integral part of modern spintronics devices owing to its rich underneath spin–orbital physics. [ABSTRACT FROM AUTHOR]

Untethered magnetic soft robots capable of performing adaptive locomotion and shape reconfiguration open up possibilities for various applications owing to their flexibility. However, magnetic soft robots are typically composed of soft materials with fixed modulus, making them unable to exert or withstand substantial forces, which limits the exploration of their new functionalities. Here, water‐induced, shape‐locking magnetic robots with magnetically controlled shape change and water‐induced shape‐locking are introduced. The water‐induced phase separation enables these robots to undergo a modulus transition from 1.78 MPa in the dry state to 410 MPa after hydration. Moreover, the body material's inherent self‐healing property enables the direct assembly of morphing structures and magnetic soft robots with complicated structures and magnetization profiles. These robots can be delivered through magnetic actuation and perform programmed tasks including supporting, blocking, and grasping by on‐demand deformation and subsequent water‐induced stiffening. Moreover, a water‐stiffening magnetic stent is developed, and its precise delivery and water‐induced shape‐locking are demonstrated in a vascular phantom. The combination of untethered delivery, on‐demand shape change, and water‐induced stiffening properties makes the proposed magnetic robots promising for biomedical applications. [ABSTRACT FROM AUTHOR]