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Materials that can provide highly spin polarized electrons or current are very relevant for spintronics device applications. Recent studies have found an interesting class of spintronics materials called spin gapless semiconductor (SGS) which has zero gap for one spin channel and a small band gap for other spin channel. Such a band structure facilitates really high spin polarization. The binary Heusler, Cr3Al with DO3 type structure is predicted to exhibit SGS characteristics. Several experiments are done on the preparation and characterization of Cr3Al films, but no experimental studies are done on bulk crystalline form. Here we have successfully synthesized Cr3Al alloy in bulk form. The room temperature XRD and Rietveld refinement studies indicate that the annealed Cr3Al is formed in DO3 type structure. The SEM images confirm the prepared samples are in single phase. The temperature dependent resistance studies reveal the weak semiconducting behavior of the prepared sample. Temperature and field dependent magnetization studies indicate ferrimagnetic order above 300 K with very small moment. The observations from the magnetization studies are very different from the previous thin film reports that confirms the antiferromagnetic ordering. [ABSTRACT FROM AUTHOR]

The special injection molding process GITBlow combines the characteristic features of injection molding and blow molding and enables the production of complex hollow body structures with low wall thickness and connected functional surfaces in one process. In the first step, a preform is created using the described gas injection technology. In the second step, this preform is further formed by a second pressurization similar to blow molding after the mold cavity has been enlarged. This results in a biaxial stretching of the preform material without further melt displacement. The advantage of the GITBlow compared to the underlying single processes GAIM and blow molding as well as other special processes is the following aspects: Independent of component geometry, material and process control, the gas injection technology has a gas limit pressure from which a maximum cavity / component cross section ratio is achieved. As a result of the second inflation process, this value can be significantly increased with the GITBlow process. Only blow molding allows similar or even lower wall thicknesses, but here the geometrical design freedom with regard to the connected functional elements and surfaces is severely restricted due to the process. The results obtained so far at the University of Paderborn have shown that, when simulating the GITBlow process, a division into the three characteristic process steps of the process is target-oriented. This means that three successive simulation steps are carried out, which are oriented to the process sequence. These are in detail: 1) Preform production by means of gas injection molding; 2) Temperature compensation by heat transport; 3) Inflation by means of a second gas injection In the first years of the project, the focus was on the simulation of the behavior of amorphous materials. The current goal is to investigate the blowing behavior of semi-crystalline materials in the GITBlow process. For this purpose, strain tests were carried out at typical GITBlow strain rates, the results of which are now to be integrated into the description of the process and shall be described in this thesis. [ABSTRACT FROM AUTHOR]

Nickel ferrite (NiFe2O4) nanopowder has been synthesized by a sol-gel auto-combustion process and further sintered at various sintering temperatures. The sintered samples were characterized by XRD, SEM and VSM. Enhancement of apparent density of the sample has been observed with the increase in sintering temperature and has a great influence on the magnetic and dielectric properties of NiFe2O4. The SEM results reveal that the grain size increases with increasing sintering temperature. The electrical resistivity decreases and the dielectric constant increases with increasing sintering temperature has been observed. The magnetic studies shown that the ferrimagnetic behaviour increases with sintering temperature. These results suggest that sintering temperature has a prominent effect on the magnetodielectric properties. [ABSTRACT FROM AUTHOR]

In this paper, we studied the effect of temperature on the magnetic properties of GdCo-Al2O3 composite films. These films were obtained by magnetron co-sputtering of Gd, Co, and Al2O3 targets in an Ar atmosphere. The magnetic properties were investigated using a vibrating sample magnetometer in the temperature range from 5 to 300 K. It was found that the formation of ferrimagnetic ordering is possible in GdCo-Al2O3 films. Furthermore, the larger the content of the Al2O3 dielectric phase in the film is, the larger volume of Gd undergoes oxidation. [ABSTRACT FROM AUTHOR]

The influence of the thickness of the nanoscale ferrimagnetic Tb-Co layers on the magnetic properties of Tb-Co/Ti multilayers was studied. The fanning cone angle of Tb-Co sperimagnetic structure changes non-monotonously with a decrease of the Tb-Co layer thickness. The reason for this behavior of the fanning cone angle is discussed taking into account a possible reduction of the Co atom moment because of the electron charge transfer from atoms of the non-magnetic spacers to atoms of the transition metal. [ABSTRACT FROM AUTHOR]

One of the main components which is used as a cathode in Lithium-ion battery is Vanadium pentoxide [V2O5] nanostructure. 2D nanostructures of V2O5 increases the effective contact area between the electrolyte and active material which increases the storage capacity of Lithium ions and shorten the diffusion distance of the lithium ions.Reduced graphene oxide [RGO] also has the properties to be a cathode in Lithium ion battery. It is reported that the electrically insulating metal oxide nanostructures are absorbed onto RGO to increase the performance of the batteries. Following that, a nanocomposite was made from RGO and V2O5. V2O5 nanostructures were synthesized from ammonium metavanadate. Graphene oxide [GO] were synthesized by modified Hummer's method and then it was reduced to RGO. Nanofibril V2O5 and RGO were mixed together in 1:1 ratio and coated over ITO glass plates by spin coating technique. These films were kept under different temperatures. XRD and FESEM images were analyzed for morphological studies. For electrochemical analysis, cyclic voltammograms were taken for the prepared film as working electrode. Cyclic voltammetry analysis shows that the prepared RGO: V2O5 Nanofibril composite film is best suited for the use in Lithium-ion batteries. [ABSTRACT FROM AUTHOR]

A series of nickel cadmium ferrite nanoparticles synthesized using one step auto combustion technique. The magnetic properties of these synthesized samples determined using Zero Field NMR and the Vibrating sample Magnetometry techniques. The plot of NMR as a function frequency exhibits two peaks corresponding to the octahedral (A) and the tetrahedral (B) sites of the Fe3+ ions. A qualitative correlation is found between the saturation magnetization obtained from VSM and the spin echo signal amplitude measured at the B-site from the NMR. This could be explained by considering the behavior the domains to the applied external magnetic field and the radiofrequency field (rf enhancement in the ferrimagnetic materials). [ABSTRACT FROM AUTHOR]

We report the structural, magnetic and electronic properties of quaternary Heusler alloy CoRhTiAl. Room temperature XRD analysis reveals that the alloy crystallizes in B2-type structure instead of perfectly ordered Y-type structure due to 50 % disorder between the tetrahedral sites (Co and Rh) as well as octahedral sites (Ti and Al). The ab-initio simulations with GGA+U method predict a perfectly half-metallic ferrimagnetic nature with a gap in the minority spin-channel and thus, a high spin polarization. [ABSTRACT FROM AUTHOR]

Nanocrystalline cobalt ferrite (CoFe2O4) was synthesized through a sol-gel reaction route and characterized by powder XRD and SQUID magnetometry measurements. Rietveld profile refinement of XRD pattern confirmed formation of single phase nanocrystalline CoFe2O4 in the fcc symmetry with an average particle size of ~16nm. CoFe2O4 display soft ferrimagnetic behavior at 300K with a saturation magnetization of ~74emu/g, remanence of ~27emu/g and coercivity of 1.66kOe. M-H curve recorded at 5K showed wasp-waisted hysteresis loop with a saturation magnetization of 80emu/g, very high coercivity of 13.52kOe and 59emu/g remanence. Temperature dependence of ZFC and IFC modes of magnetization are suggestive of superspin glass state below 100K in CoFe2O4 nanoparticles. Superposition of superspin glass and superparamagnetic phases in the CoFe2O4 lattice at 5K leads to the wasp-waisted hysteresis loop. [ABSTRACT FROM AUTHOR]

The nanocomposites of hard ferromagnetic BaFe12O19 and soft ferrimagnetic CuFe2O4 have been synthesized by the citrate sol-gel method which is calcined at different temperatures (800°C and 1000°C). The crystal structure, microstructural morphology, and magnetic properties were studied by employing the X-Ray Diffraction(XRD), Field- Emission Scanning Electron Microscopy(FE-SEM) and Vibrating Sample Magnetometer(VSM) techniques respectively. The exchange coupling of hard-soft magnetic nanocomposite materials have been explained by the “Henkel plot”. The nature of exchange interaction and magnetic dipole interaction of nanocomposites have been studied from δm vs H plots. This article gives the easy and inexpensive method for the preparation of hard-soft nanocomposites of magnetic materials and enhances its magnetic properties. [ABSTRACT FROM AUTHOR]

In this investigation the structural properties and Mössbauer parameters of Ce doped cobalt ferrite nanoparticles are presented. The preparation of the sample is done by nitrate route using sol-gel method and samples are sintered at 300oC for one hour. The XRD pattern shows the pure phases of ferrite in both pure and doped sample of cobalt ferrite. The XRD pattern of cerium doped sample is more scattered then pure sample which indicates that crystallization is weakening when a small amount of cerium is doped. After doping a decrease in particle size is (12nm for pure and 8nm for doped sample) found, this decrease is also verified by the presence of large doublet in Mössbauer spectra. The Mössbauer spectra show two sets of sextets and one doublet in pure as well as in cerium doped sample. Two sextets signify the ferrimagnetic nature of the sample and the doublet is attributed to the presence of superparamagnetic particles in the specimen. A structural formula is calculated by using Mössbauer parameters for both the samples and a substantial effect is found in cationic distribution between A and B sites. Magnetic moment per formula unit is also calculated in this study the values are found for pure and doped samples 4.314μB and 4.596μB respectively. [ABSTRACT FROM AUTHOR]

We investigated the phase diagram of cubic Cu2OSeO3 using temperature dependent magnetic susceptibility and Arrot plot analysis. Different five phases have been observed in Cu2OSeO3 viz: single domain conical, multidomain helical, ferrimagnetic, paramagnetic and skyrmion known as A-phase.The skyrmion phase has been explored in the temperature range from 54 K to 59 K and in the applied magnetic field range from 15 mT to 30 mT. [ABSTRACT FROM AUTHOR]

Inverse Heusler alloy Cr2CoAl has been prepared by arc melting. XRD and Reitveld refinement study indicates XA lattice with B2 disorder. Magnetization measurement indicates that this alloy is ferrimagnetic below Tc=28K with soft magnetic behavior as observed from M-H curve at 4K. We observe a deviation from Curie-Weiss nature above Tc. We also observe negative magnetization in certain temperature range only when magnetization is measured at very low magnetic fields and in zero field cooled (ZFC) condition. The observed negative magnetization is not caused by the negative magnetic field trap in the magnetometer solenoid as suggested by others earlier but it appears as if the system have two competing magnetic component having positive and negative magnetization contribution. This issue is addressed in this report. [ABSTRACT FROM AUTHOR]

We report the structural, magnetic and electronic properties of cubic MnV2O4 with two magnetic phases ferrimagnetic (FIM) and non-magnetic (NM) using the density functional theory. Among the studied phases of MnV2O4 the minimum energy phase is ferrimagnetic phase with all Mn and V atoms consist down spin and up spin respectively. Distorted octahedral geometry with angular distortion of 6° is observed in FIM phase from the perfect octahedron, which is more than the NM magnetic phase. The bond lengths reduce in the case of NM phase of MnV2O4 compared to NM phase. Projected density of states analysis shows that the metallic behaviour in spin up configuration of FIM phase is due to the V-3d orbitals, while spin down configuration shows the semiconducting behaviour, which concludes that FIM phase is semi metallic in nature. [ABSTRACT FROM AUTHOR]

59Co-Internal Field Nuclear Magnetic Resonance (IFNMR), 57Fe-IFNMR measurements are carried for the different materials like bulk cobalt, carbon coated cobalt (Co@C), bulk iron, carbon coated iron nanoparticles (Fe@C). The comparison of obtained results for bulk cobalt and Co@C shows that the bulk cobalt exists in the both the phases i.e., fcc and hcp phases, while the other exist only in the fcc phase. Further, the comparison of the NMR results of bulk iron and Fe@C confirms the presence of the single domain particles in the Fe@C samples. Thus, we propose IFNMR as a powerful tool to identify the structural and magnetic properties of ferro/ferrimagnetic materials. [ABSTRACT FROM AUTHOR]

We investigated the phase diagram of cubic Cu2OSeO3 using temperature dependent magnetic susceptibility and Arrot plot analysis. Different five phases have been observed in Cu2OSeO3 viz: single domain conical, multidomain helical, ferrimagnetic, paramagnetic and skyrmion known as A-phase.The skyrmion phase has been explored in the temperature range from 54 K to 59 K and in the applied magnetic field range from 15 mT to 30 mT. [ABSTRACT FROM AUTHOR]

We report the structural, magnetic and electronic properties of cubic MnV2O4 with two magnetic phases ferrimagnetic (FIM) and non-magnetic (NM) using the density functional theory. Among the studied phases of MnV2O4 the minimum energy phase is ferrimagnetic phase with all Mn and V atoms consist down spin and up spin respectively. Distorted octahedral geometry with angular distortion of 6° is observed in FIM phase from the perfect octahedron, which is more than the NM magnetic phase. The bond lengths reduce in the case of NM phase of MnV2O4 compared to NM phase. Projected density of states analysis shows that the metallic behaviour in spin up configuration of FIM phase is due to the V-3d orbitals, while spin down configuration shows the semiconducting behaviour, which concludes that FIM phase is semi metallic in nature. [ABSTRACT FROM AUTHOR]

The Mn2 based Heusler compounds are of great interest due to their potential ferrimagnetic properties & high spin polarization ratio. First principle calculation using ab initio density functional theory using ultra soft pseudo potential and generalized gradient approximation (GGA) with implementation of spin have been used to calculate the structural, magnetic and electronic properties of Mn2RhSi. The present study reveals that the Mn2RhSi is stable in Hg2CuTi type structure and exhibit half metallic ferromagnetic nature at equilibrium lattice constant. Total magnetic moment of Mn2RhSi is about 3.00 µB which obeys Slater Pauling (SP) rule M" = Z"-24. Antiparallal spin magnetic moment of Mn (I) and Mn (II) atoms which confirms the half-metallic nature of material. The present values of magnetic moment and lattice constant agree with previously reported results. High value of spin polarization ratio is critical for enhancement of efficiency of spintronics devices. [ABSTRACT FROM AUTHOR]

BaFe12O19 Nanoparticles are prepared through auto ignition method and structure, microstructure and magnetic properties are characterized. Samples having spherical shapes and elongated nanorods are chosen to investigate the role of finite size effect in magnetic properties. Magnetization studies show superparamagnetic, antiferromagnetic and ferrimagnetic behaviors depending on the size and shape. Very small coercive field of around 200 Oe is observed for spherical nanoparticles and a large coercive field of around 7000 Oe for nanorods is found. The shape and size plays an important role in magnetic properties of BaFe12O19 nanoparticles. Shape anisotropy has significant value compared to other anisotropies. Therefore shape of nanoparticles influences the magnetic order. [ABSTRACT FROM AUTHOR]

BaFe12O19 Nanoparticles are prepared through auto ignition method and structure, microstructure and magnetic properties are characterized. Samples having spherical shapes and elongated nanorods are chosen to investigate the role of finite size effect in magnetic properties. Magnetization studies show superparamagnetic, antiferromagnetic and ferrimagnetic behaviors depending on the size and shape. Very small coercive field of around 200 Oe is observed for spherical nanoparticles and a large coercive field of around 7000 Oe for nanorods is found. The shape and size plays an important role in magnetic properties of BaFe12O19 nanoparticles. Shape anisotropy has significant value compared to other anisotropies. Therefore shape of nanoparticles influences the magnetic order. [ABSTRACT FROM AUTHOR]

Barium ferrite (BaFe12O19, BaM) thin films were fabricated by the spin coating of precursors obtained by using a sol--gel method. The effects of the rotational speed on the spin-coating process for growing a BaM thin film were investigated in this study. Coated films were heat-deposited at different rotational speeds ranging from 2000 to 4000 rpm, while the number of layers was set to nine. Further, the effect of the number of layers on the growth of BaM thin films was discussed. For this purpose, we take the layers number 1 to 12 and take the constant rotational speed of 3000 rpm. All the film were characterized using X-Ray diffraction, Scanning Electron microscope, and Energy-dispersive X-Ray spectroscopy and Vibrating Sample Magnetometer. It was found that by increasing the rotational speed the amount of material deposited on the Si substrate decreased. The measured grain size of the BaM thin film was nearly similar for three three different rotational speeds. However, the grain size was found to increase the number of layers. [ABSTRACT FROM AUTHOR]

Magnetization measurements were carried out for polycrystalline Mn1.9Cu0.1Sb in magnetic fields up to 5 T in the 10-300 K temperature range under high pressures up to 1 GPa in order to investigate the magnetic properties and the thermal transformation arrest (TTA) phenomenon under high pressures. The spin-reorientation temperature increased from 202 K for 0.1 MPa to 244 K for 1 GPa, whereas the transition temperature from the ferrimagnetic (FRI) to antiferromagnetic (AFM) state did not drastically change at ~116 K. The magnetic relaxation behavior from the FRI to AFM state was observed in 10 < T ≤ 70 K, which was analyzed using the Kohlrausch-Williams-Watts model. Obtained results indicated that the TTA phenomenon of Mn1.9Cu0.1Sb was suppressed by the application of high pressures. [ABSTRACT FROM AUTHOR]

Comparative study of magnetite (Fe3O4) thin films grown by pulsed laser ablation (PLD) and radio frequency (RF)-sputtering of α-Fe2O3 target have been investigated. We have found strong correlation between RF power (P) of sputtering and substrate temperature (Ts) of PLD films on their structural and magnetic properties. Films grown at low P and Ts are dominated by antiferromagnetic α-Fe2O3 phase while ferrimagnetic Fe3O4 phase is dominant at high P and Ts Post-annealing in H2/H2O atmosphere at 450 °C, these films show single phase Fe3O4 but RF power and substrate temperature still play a significant role. With increasing P and Ts values, the orientation of Fe3O4 films change from (110) to (111) followed by complete randomizations. These (110) to (111) orientations affect magnetic properties differently above Verwey transition temperature of 120 K. The RF-power and substrate temperature have the same influence on the physical properties of Fe3O4 films, as both are related to thermal energy. [ABSTRACT FROM AUTHOR]

A composite system BaFe12O19/SrTiO3 with ferrimagnetic BaFe12O19 phase (BHF) and ferroelectric SrTiO3 phase (STO) have been prepared by mechanical alloying and subsequent heat treatment. The composite powders were studied by Particle Size Analyze, X-ray diffraction and magnetic measurement. It was found that the particle size of composite powders initially increased due to laminated layers formation of a composite and then decreased to an asymptotic value of ~8 μm as the milling time extended even to a relatively longer time. However, based on results of line broadening analysis the mean grain size of the particles was found in the nanometer scale. We thus believed that mechanical blending and milling of mixture components for the composite materials has promoted heterogeneous nucleation and only after successive sintering at 1100 °C the milled powder transformed into particles of nanograin. In this report, microstructure as well as magnetic properties for the composite is also briefly discussed. [ABSTRACT FROM AUTHOR]

The analytic solution of the model is obtained using the method of mapping. One observes ferromagnetic and ferrimagnetic phases, and the reentrance phenomenon. For a certain range of interaction parameters between nearest neighbors, as a result of geometrical frustration, the ground state is degenerate, but nevertheless the system exhibits phase transition at a finite critical temperature accompanied by coexistence of order and disorder. [ABSTRACT FROM AUTHOR]

This paper presents the miniaturization of the microstrip antenna on ferrimagnetic substrate for operate at a frequency of 2.5 GHz, where the full wave method Transverse Transmission Line-TTL is used it for obtain resonance frequency. For validate this method in these substrates, the results as function of DC magnetic field are shown. When the field is 132.6 AT/m, the value of reference is 151.7 MHz and the value of TTL is 151.3 MHz. The dimensions are obtained for the frequency of 2.5 GHz and a comparison is done with ferrites and conventional substrate, showing a reduction in volume of the antenna of 2808.96 mm3 for 0.39 mm3 when the ferrites are used. [ABSTRACT FROM AUTHOR]

For the first time, we report the effect of high energy gamma irradiation induced structural and magnetic properties of nanocrystalline Mn0.5Zn0.5ScyFe2-yO4 (y = 0.01, 0.03 and 0.05) samples synthesized by solution combustion method using a mixture of fuels. All samples were exposed to a dose of 25 kGy gamma radiations originating from a 60Co source. The as prepared samples and the samples after gamma irradiation were characterized by X-ray diffraction, Fourier transform Infrared spectroscopy and vibrating sample magnetometry at RT. The XRD results reveal that all the pristine samples have shown single phase cubic structure before and after gamma irradiation. The lattice parameter increases on increasing Sc3+ content after gamma irradiation. FTIR reveals that, after gamma irradiation the absorption peaks are shifted to higher frequency. In M-H loops, we observe decrease in saturation magnetization, remnant and coercivity of the samples due to breaking of ferrimagnetic ordering, when a high energy gamma ray passed through the material. Our results are important for understanding the stability and performance of the materials and the devices used in various technological applications. [ABSTRACT FROM AUTHOR]

The mixed spinel, MgFe2O4 has been synthesized by ball-milling assisted sintering method. X-ray diffraction study confirms formation of cubic MgFe2O4 and the lattice parameter values calculated are a = b = c = 8.369(3) Ö. Vibrating sample magnetometer measurements at room temperature shows a soft ferrimagnetic nature. Magneto-Dielectric and Magneto-Restive plots confirm coupling at room temperature in the prepared MgFe2O4. The peak at 500 Oe in the MD plot is due to the canting of Fe3+ ions distributed in octahedral and tetrahedral sites. [ABSTRACT FROM AUTHOR]

We report here the effect of 30% Mn substitution on structure and magnetic properties of multiferroic CoCr2O4. Room temperature neutron diffraction studies were carried out on polycrystalline Co(Cr1-xMnx)2O4 (x=0.00 and 0.30) samples to determine structural properties. It has been observed that 30% Mn substitution for Cr in CoCr2O4 leads to increase in the ferrimagnetic transition temperature, (Tc) from ~96 K to ~114 K along with the magnetostructural transition temperature, (Ts) from ~26 K to ~32 K. In addition, optical properties were studied by UV-visible technique in the range of 200-800 nm. The energy band gap is found to decrease in compare to parent compound. Both magnetization and band gap variation can be explained using the spin-exchange interactions present in these systems. [ABSTRACT FROM AUTHOR]

The structural and the temperature-dependent exchange bias properties of room temperature reactive sputtered Fe3O4 (150 nm) thin films are studied. The structural study shows that the films are polycrystalline with no preferred orientation. The exchange bias measurement performed at various temperatures shows a consistent increase in the magnitude of exchange bias field (HEB) as the temperature is lowered from 300 K, and showing a significant increase at low temperatures, which reaches a value of HEB = 190 Oe at 2 K. The presence of exchange bias effect is mainly due to the existence of a non-negligible exchange coupling between the core spins and the surface spins of Fe3O4 grains. [ABSTRACT FROM AUTHOR]

The mixed spinel, MgFe2O4 has been synthesized by ball-milling assisted sintering method. X-ray diffraction study confirms formation of cubic MgFe2O4 and the lattice parameter values calculated are a = b = c = 8.369(3) Ö. Vibrating sample magnetometer measurements at room temperature shows a soft ferrimagnetic nature. Magneto-Dielectric and Magneto-Restive plots confirm coupling at room temperature in the prepared MgFe2O4. The peak at 500 Oe in the MD plot is due to the canting of Fe3+ ions distributed in octahedral and tetrahedral sites. [ABSTRACT FROM AUTHOR]

CuCr2Se4 is a potentially attractive versatile material, from the point of view of spintronics application. It shows characteristics of a ferromagnetic conductor at room temperature and with suitable doping it is proposed to show half-metallicity. With an aim to understand the effect of doping at Cr-site by a non-magnetic ion, we carried out investigation of magnetic and crystal structure properties of polycrystalline CuCr2Se4 and CuCr1.5Ti0.5Se4 spinel. These materials were prepared by solid state synthesis and characterized using room temperature powder XRD and measurement of magnetic properties. The XRD patterns were analyzed using Rietveld technique and lattice constants were estimated. Formation of a small amount of Cr3Se4 phase was identified from the XRD profiles. However, the magnetic properties do not seem to be affected much by it. Compared to parent compound, CuCr2Se4, the ferromagnetic Curie temperature TC in CuCr1.5Ti0.5Se4 was found to decrease to 208 K. But its magnetic moment (µB/f.u.) determined from the saturation magnetization value measured at 5 K, differed only slightly from that of CuCr2Se4. Our preliminary results are presented here. [ABSTRACT FROM AUTHOR]

CuCr2Se4 is a potentially attractive versatile material, from the point of view of spintronics application. It shows characteristics of a ferromagnetic conductor at room temperature and with suitable doping it is proposed to show half-metallicity. With an aim to understand the effect of doping at Cr-site by a non-magnetic ion, we carried out investigation of magnetic and crystal structure properties of polycrystalline CuCr2Se4 and CuCr1.5Ti0.5Se4 spinel. These materials were prepared by solid state synthesis and characterized using room temperature powder XRD and measurement of magnetic properties. The XRD patterns were analyzed using Rietveld technique and lattice constants were estimated. Formation of a small amount of Cr3Se4 phase was identified from the XRD profiles. However, the magnetic properties do not seem to be affected much by it. Compared to parent compound, CuCr2Se4, the ferromagnetic Curie temperature TC in CuCr1.5Ti0.5Se4 was found to decrease to 208 K. But its magnetic moment (µB/f.u.) determined from the saturation magnetization value measured at 5 K, differed only slightly from that of CuCr2Se4. Our preliminary results are presented here. [ABSTRACT FROM AUTHOR]

Thin film of Fe3O4 is grown on (100) oriented GaAs substrate using pulsed laser deposition (PLD). The films were found to be (111) oriented. They were characterized morphologically as well as magnetically. They show Verwey transition at 120 K with the coercivity of 220 Oe at room temperature. These films were found to show magnetoimpedance effect with the ac magnetoresistance (MRac) of the order of ~ -6% at 10 MHz, at room temperature. The MRac was found to increase in low field- low frequency regime and decrease in low field high frequency regime. [ABSTRACT FROM AUTHOR]

Magnetic domains in the ferrimagnetic state of Co doped Mn2Sb single crystal has been visualized using Magnetic Force Microscopy. It shows fractal like domain structure. With the application of magnetic field, single domain state is achieved around 2000 Oe. The MFM images collected during field increasing and decreasing cycles show different morphology for same field value. [ABSTRACT FROM AUTHOR]

We have studied the structural, magnetic and magnetodielectric measurements of polycrystalline Ni0.5Co0.5Cr2O4. The magnetic measurement shows that Curie temperature is 80 K for the spinel ferrimagnet Ni0.5Co0.5Cr2O4. We found another magnetic transition at 33K besides Curie temperature. Magnetodielectric measurements of Ni0.5Co0.5Cr2O4 suggest an anomaly at 45 K. Below Curie temperature (45 K), a strong magnetic field dependence of the dielectric constant is observed with cusp-like curve. The strength of the large magnetodielectric response in this system can be explained by optimal spin-orbit coupling. [ABSTRACT FROM AUTHOR]

The polycrystalline single phase Ba2Mg2Fe12O22 (BMF) and Ba2Mg2Fe11.52Mn0.48O22 (BMFM) were prepared using conventional solid state reaction route. We report the modification in structural, dielectric and magnetic properties of BMF due to 4% Mn doping at Fe site. Phase purity of both sample are confirmed by the Reitveld refinement of XRD data. Temperature dependent dielectric study shows decrease in dielectric constant (ε’) and dielectric loss (tan δ) due to 4% Mn doping in parent sample. The ferrimagnetic to paramagnetic transition temperature (Tc) in doped sample decreases from 277°C to 150°C. Room temperature magnetization measurement shows ferrimagnetic behavior for both the samples. We have fitted the saturation magnetization data at 300 K by using least square method which confirms the enhancement of saturation magnetization and magnetic anisotropy constant in doped sample. [ABSTRACT FROM AUTHOR]

The crystal structure, magnetic properties and magnetocaloric effect (MCE) of Co(Cr0.95Fe0.05)2O4 have been studied. Co(Cr0.95Fe0.05)2O4 synthesized by solid-state reaction method, crystallizes in normal cubic spinel structure with Fd-3m space group. Neutron powder diffraction (NPD) and magnetic measurements when compared to the undoped CoCr2O4, show that the compound is ferrimagnetic (FIM) and transition temperature (TC) is enhanced due to Fe substitution. Analysis of structural and magnetic properties shows the existence of two different sites of magnetic clusters due to Fe/Cr cation disorder. The competition between the moments of the two different sub-lattices gives rise to the temperature induced magnetization reversal at compensation tempearature (Tcomp) = 44 K. The magnetocaloric effect (simply the change in magnetic entropy i.e, −ΔSM) has been observed in Co(Cr0.95Fe0.05)2O4 with different applied magnetic fields (max. H = 90 kOe). We found maximum change of magnetic entropy ∼1.2 J/kg K, for a field change of 90 kOe at FIM transition temperature (TC∼110 K) with relative cooling power (RCP) of ∼13 J/kg. Moreover, the sign change of −ΔSM across the compensation temperature (Tcomp∼ 44 K) shows another phase transition across Tcomp in Co(Cr0.95Fe0.05)2O4. The values of MCE and RCP are also appreciable so as to consider Co(Cr0.95Fe0.05)2O4 as a magnetic refrigerant above liquid nitrogen temperature. [ABSTRACT FROM AUTHOR]

We have studied the structural, magnetic and magnetodielectric measurements of polycrystalline Ni0.5Co0.5Cr2O4. The magnetic measurement shows that Curie temperature is 80 K for the spinel ferrimagnet Ni0.5Co0.5Cr2O4. We found another magnetic transition at 33K besides Curie temperature. Magnetodielectric measurements of Ni0.5Co0.5Cr2O4 suggest an anomaly at 45 K. Below Curie temperature (45 K), a strong magnetic field dependence of the dielectric constant is observed with cusp-like curve. The strength of the large magnetodielectric response in this system can be explained by optimal spin-orbit coupling. [ABSTRACT FROM AUTHOR]

The polycrystalline single phase Ba2Mg2Fe12O22 (BMF) and Ba2Mg2Fe11.52Mn0.48O22 (BMFM) were prepared using conventional solid state reaction route. We report the modification in structural, dielectric and magnetic properties of BMF due to 4% Mn doping at Fe site. Phase purity of both sample are confirmed by the Reitveld refinement of XRD data. Temperature dependent dielectric study shows decrease in dielectric constant (ε’) and dielectric loss (tan δ) due to 4% Mn doping in parent sample. The ferrimagnetic to paramagnetic transition temperature (Tc) in doped sample decreases from 277°C to 150°C. Room temperature magnetization measurement shows ferrimagnetic behavior for both the samples. We have fitted the saturation magnetization data at 300 K by using least square method which confirms the enhancement of saturation magnetization and magnetic anisotropy constant in doped sample. [ABSTRACT FROM AUTHOR]

The crystal structure, magnetic properties and magnetocaloric effect (MCE) of Co(Cr0.95Fe0.05)2O4 have been studied. Co(Cr0.95Fe0.05)2O4 synthesized by solid-state reaction method, crystallizes in normal cubic spinel structure with Fd-3m space group. Neutron powder diffraction (NPD) and magnetic measurements when compared to the undoped CoCr2O4, show that the compound is ferrimagnetic (FIM) and transition temperature (TC) is enhanced due to Fe substitution. Analysis of structural and magnetic properties shows the existence of two different sites of magnetic clusters due to Fe/Cr cation disorder. The competition between the moments of the two different sub-lattices gives rise to the temperature induced magnetization reversal at compensation tempearature (Tcomp) = 44 K. The magnetocaloric effect (simply the change in magnetic entropy i.e, −ΔSM) has been observed in Co(Cr0.95Fe0.05)2O4 with different applied magnetic fields (max. H = 90 kOe). We found maximum change of magnetic entropy ∼1.2 J/kg K, for a field change of 90 kOe at FIM transition temperature (TC∼110 K) with relative cooling power (RCP) of ∼13 J/kg. Moreover, the sign change of −ΔSM across the compensation temperature (Tcomp∼ 44 K) shows another phase transition across Tcomp in Co(Cr0.95Fe0.05)2O4. The values of MCE and RCP are also appreciable so as to consider Co(Cr0.95Fe0.05)2O4 as a magnetic refrigerant above liquid nitrogen temperature. [ABSTRACT FROM AUTHOR]