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In view of tuning different transitions, Co and V are substituted in Mn-rich Ni-Mn-Ga alloy. Ni41Co9Mn30V2Ga18 sample undergoes a coupled magnetostructural transition above room temperature with a low thermal and magnetic hysteresis and high sensitivity of martensite transition temperature (8 K/T) with the field. ∆SM is found to be a maximum of −2.33 J/kg-K for 3 T field change with a large RCP of 158 J/kg. The presence of intermartensite transition along with the magnetostructural transition widens the range of working temperature. [ABSTRACT FROM AUTHOR]

With an aim to explore the d0 ferromagnetism in Ag-doped ZnO compounds, the poly-crystalline samples of Zn 1 - x Ag x O (with 0 ≤ x ≤ 0.12) were synthesized by a standard solid-state synthesis technique. The XRD analyses indicated that these compounds have been formed as Ag:ZnO nanocomposite. According to scanning electron microstructural study, all compounds have a homogenous nearly spherical shape morphology. The EDS spectra reveal that the final produced compounds do not contain any unwanted external impurity. The magnetization versus field measurement at room temperature demonstrates that the undoped ZnO compound shows ferromagnetism embedded in diamagnetic matrix, whereas all Ag-doped ZnO samples exhibit a clear room temperature ferromagnetic behavior with coercivity values between 80 and 196 Oe. The maximum saturation magnetization was obtained for the Zn0.97Ag0.03O sample; however, it declines subsequently. The bound magnetic polarons (BMPs) has been considered to explain the observed ferromagnetic behavior. [ABSTRACT FROM AUTHOR]

Polycrystalline [(0.5) Bi0.5Na0.5TiO3-(0.5) LaFeO3] multiferroic composite is prepared by using the solid-state reaction method. The crystal structure of both phases is characterized by using the X-ray diffraction method (XRD) and confirms the presence of rhombohedral (i.e., bismuth sodium titanate) and orthorhombic (i.e., lanthanum ferrite) phases in the composite. The microstructure of the composite is analyzed using field emission scanning electron microscopy (FESEM). The crystal structure is further studied with Raman spectroscopy. The present composite exhibits ferroelectric and ferrimagnetic-like properties, revealing its multiferroic behavior. Furthermore, the impedance analysis of the composite shows the negative temperature coefficient of resistance behavior. The present study describes the structural and physical properties of the possible lead-free multiferroic composite. [ABSTRACT FROM AUTHOR]

Magnetic studies on aluminum-substituted cobalt ferrite nanoparticles (CoFeAl O ) of average particle size ∼20 nm in the broad range of temperature varying from room temperature (300 K) to 900 K has been presented. The temperature dependence of DC magnetization curve exhibits paramagnetic to ferrimagnetic transition at ∼736 K. Zero field cooling and field cooling magnetization measurement shows that the blocking temperature is far above the room temperature. The presence of ferrimagnetic order in the sample has been analyzed by Arrott plot technique for M-H data measured over the temperature range 300-900 K in the magnetic field of ±9 T. The magnetocrystalline anisotropy constant was determined by employing the 'law of approach (LA) to saturation' theory. The saturation magnetization, magnetocrystalline anisotropy constant and coercivity are found to decrease with the increase in temperature. [ABSTRACT FROM AUTHOR]

The DC magnetic hysteresis loop measurements were carried out for temperatures varying from 5 to 300 K over a field range of ±10 T on nanocrystalline (∼35 nm) cobalt ferrite samples (crystallized to $Fd\bar {3} m$ space group with cubic symmetry) to validate the law of approach at low temperature for the nanocrystalline cobalt ferrite. A magnetocrystalline anisotropy constant and saturation magnetization have been obtained by analyzing the magnetization curve in saturation using the 'law of approach (LA) to saturation.' The magnetocrystalline anisotropy constant is found to be almost constant in the temperature range of 5 to 150 K due to the freezing of spin at low temperature. Also, spin freezing leads to a decrease of coercivity with the increase in the temperature. [ABSTRACT FROM AUTHOR]