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Most of the ferromagnetic shape memory (FSM) Heusler alloys, which are primarily studied in bulk form in the literature, exhibit p-d type hybridization. This study conducts a thorough multidirectional investigation of a strongly d-d hybridized quinary melt-spun annealed ribbon having the composition Ni35Mn34.5Co14Fe1Ti15.5 (NMCFT-1). This off-stoichiometric, polycrystalline FSM, fabricated using the melt-spin technique, exhibits a highly textured microstructure, double magnetic transitions and super-mechanical features mitigating brittleness. It crystallizes in a perfectly B2-type disorder austenite (Pm-3m, space group number 221) phase at room temperature. It has been hypothesized that geometric frustration is the causative factor for this disorder. Curie temperature of austenite phase ( T C A ) between paramagnetic → ferromagnetic state is found to be ∼364.57 K, whereas martensite transformation temperature from weak magnetic martensite state to ferromagnetic austenite state is ∼174.74 K. Calculated moments (effective moment, μ eff = 5.12 μ B ; low-temperature saturation moment, μ S (or M S (0) ) = 5.08 μ B ) yield a Rhodes–Wohlfarth ratio of ∼1, indicating the existence of the non-itinerant nature of 3d electrons, whereas the ferromagnetism and the linear or non-linear dependency of M s 2 (T ) on T 2 around T C A indicates the presence of long-range Rudermann–Kittel–Kasuya–Yosida-type interaction. More importantly, the maximum magnetic entropy change ( Δ S m ) obtained across the first-order magneto-structural transition and second-order magnetic transition are +18.2 J·kg−1K−1 at 6 T and −8.8 J·kg−1K−1 at 2 T, respectively, while a very high working temperature span (Δ T FWHM) of 28.561 K and 6.922 K are found for the same condition. The sample exhibits a significant relative cooling power of 402.98 J·kg−1 at a magnetic field of 6 T across the FOMT and 60.19 J·kg−1 at a 2 T field across the SOMT, respectively, along with excellent mechanical features such as a Vickers hardness (HV) of 411.80 HV (∼4.04 GPa). Meanwhile, Chen's super hard model fails to predict the ribbon's HV value, but Miao's hard model does, indicating that the ribbon is hard but not super hard. It also paves the way for additional investigation into innovative FSMs like this. [ABSTRACT FROM AUTHOR]

Most of the ferromagnetic shape memory (FSM) Heusler alloys, which are primarily studied in bulk form in the literature, exhibit p-d type hybridization. This study conducts a thorough multidirectional investigation of a strongly d-d hybridized quinary melt-spun annealed ribbon having the composition Ni35Mn34.5Co14Fe1Ti15.5 (NMCFT-1). This off-stoichiometric, polycrystalline FSM, fabricated using the melt-spin technique, exhibits a highly textured microstructure, double magnetic transitions and super-mechanical features mitigating brittleness. It crystallizes in a perfectly B2-type disorder austenite (Pm-3m, space group number 221) phase at room temperature. It has been hypothesized that geometric frustration is the causative factor for this disorder. Curie temperature of austenite phase ( T C A ) between paramagnetic → ferromagnetic state is found to be ∼364.57 K, whereas martensite transformation temperature from weak magnetic martensite state to ferromagnetic austenite state is ∼174.74 K. Calculated moments (effective moment, μ eff = 5.12 μ B ; low-temperature saturation moment, μ S (or M S (0) ) = 5.08 μ B ) yield a Rhodes–Wohlfarth ratio of ∼1, indicating the existence of the non-itinerant nature of 3d electrons, whereas the ferromagnetism and the linear or non-linear dependency of M s 2 (T ) on T 2 around T C A indicates the presence of long-range Rudermann–Kittel–Kasuya–Yosida-type interaction. More importantly, the maximum magnetic entropy change ( Δ S m ) obtained across the first-order magneto-structural transition and second-order magnetic transition are +18.2 J·kg−1K−1 at 6 T and −8.8 J·kg−1K−1 at 2 T, respectively, while a very high working temperature span (Δ T FWHM) of 28.561 K and 6.922 K are found for the same condition. The sample exhibits a significant relative cooling power of 402.98 J·kg−1 at a magnetic field of 6 T across the FOMT and 60.19 J·kg−1 at a 2 T field across the SOMT, respectively, along with excellent mechanical features such as a Vickers hardness (HV) of 411.80 HV (∼4.04 GPa). Meanwhile, Chen's super hard model fails to predict the ribbon's HV value, but Miao's hard model does, indicating that the ribbon is hard but not super hard. It also paves the way for additional investigation into innovative FSMs like this. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2), the most widely explored transition metal dichalcogenide, is a promising candidate for developing high-performance photodetectors due to having a wide range of electric and optoelectronic properties. However, the controlled synthesis of a highly crystalline large-area MoS2 thin film and the effect of noble metal (Au, Ag) nanoparticles and TM (Co) ion doping on its photoelectrical properties are still challenging. Herein, we report the direct growth of wafer-scale MoS2 thin films utilizing a facile polymer-free approach by a solution-phase coating process, followed by thermal annealing. A systematic study on the photoelectrical properties of the Au-, Ag-, and Co-doped (all variants are in 10 at. wt %) MoS2 photodetectors reveals that the Co-MoS2 device exhibits excellent photoresponse properties, which are also evidenced theoretically. Moreover, the Co-dopant amount is varied (5, 20 at. wt %) to decipher the impact of Co-doping on the photoresponse properties and determine the optimum doping percentage. The highest (20 at. wt %) Co-doped MoS2 photodetector exhibits good photoresponse characteristics at low voltage with minimal noise and high stability (retaining 86% of its photoresponsivity after the 30th day), attributed to the long-lived trap states, the photogating effect, more n-type doping, and generation of more charge carriers. Interestingly, the variations in Co-dopant concentrations lead to tunable photoresponse in different (blue, green, and red) laser illuminations, attributed to the band gap tunability with variable doping. This simple TM doping approach proposed in this study for improving the performance of MoS2 photodetectors can open up an avenue for research for other 2D materials, finding potential applications in photodetection and low-voltage-based operating devices. [ABSTRACT FROM AUTHOR]