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One of the induced multiferroic materials, CuO has the magnetic as well as ferroelectric phase transition at same temperature (TN1∼213 K, TC and TN2∼230 K). These type of materials can show two types of entropy; magnetic field induced entropy (Magnetocaloric Effect) as well as electeric field induced entropy (Electrocaloric Effect). The presence of both type of entropy may be called "Multicaloric Entropy" (M. Vopson, Solid State Commun. 152, 2067 (2012) and Meng et al., Phys. Lett. A 377, 567 (2013)). We observed that "Multicaloric Entropy" in the induced multiferroic materials also depends on the magnetoelectric interaction (c). Therofore, this numerical attempt to calculate the entropy of CuO may be useful for the future "electromagnetic" based refrigerator technology. [ABSTRACT FROM AUTHOR]

Among the different bulk alloys of the room temperature multiferroic compound BiFeO3, alloying with ATiO3 (A = Ba, Sr, Pb) is interesting as they have been reported to induce ferromagnetism under certain conditions. While this makes them interesting as potential multiferroic magnetoelectric materials, there is a lack of clarity on the origin of ferromagnetism in these systems. We have performed a detailed magneto-structural analysis on two alloys, namely, BiFeO3-BaTiO3 and BiFeO3-SrTiO3, and found the systems' propensity for the formation of ferrimagnetic hexaferrite (BaFe12O19 and SrFe12O19) phases. Though insignificantly small to the extent of being undetectable by x-ray powder diffraction, we prove that the ferromagnetic character of the specimen is entirely due to spontaneous precipitation of the hexaferrite grains. While our results suggest that care should be exercised before attributing ferromagnetism in such alloy systems as intrinsic to the perovskite phase, the propensity for the spontaneous precipitation of the hexaferrite phase in these multiferroic alloy systems is encouraging as it provides an opportunity for designing self-grown ferroelectric-ferromagnetic composites with good magnetoelectric coupling. [ABSTRACT FROM AUTHOR]

Abstract Polycrystalline samples of Bi 0.9 Eu 0.1 FeO 3 , Bi 0.9 Gd 0.1 FeO 3 , and Bi 0.9 Eu 0.05 Gd 0.05 FeO 3 ceramics were synthesized by a solid-state reaction method, followed by rapid quenching to room temperature. Bi 0.9 Eu 0.1 FeO 3 shows higher magnetization than Bi 0.9 Gd 0.1 FeO 3 and Bi 0.9 Eu 0.05 Gd 0.05 FeO 3. This can be explained by lattice distortion, and the change in the statistical distribution of Fe3+/Fe2+. Similarly, ferroelectric polarization of Bi 0.9 Eu 0.1 FeO 3 was found to be higher than that of Bi 0.9 Gd 0.1 FeO 3 and Bi 0.9 Eu 0.05 Gd 0.05 FeO 3. However, the absolute value of the magnetocapacitance of Bi 0.9 Eu 0.05 Gd 0.05 FeO 3 (∼1.6%) was found to be higher than that of Bi 0.9 Eu 0.1 FeO 3 (∼1.3%) and Bi 0.9 Gd 0.1 FeO 3 (∼1.1%). In addition, the quadratic component of magnetoelectric coupling is higher for Bi 0.9 Eu 0.05 Gd 0.05 FeO 3 , which makes Bi 0.9 Eu 0.05 Gd 0.05 FeO 3 attractive for further study. Highlights • The dielectric constant at room temperature of sample-3 was found to be higher than that of samples-1 and 2. • The magnetization of sample-3 was found to be greater than that of samples-1 and 2. • The polarization–electric field loop of sample-3 was found to be better than that of samples-1 and 2. • The absolute value of the magnetocapacitance of sample-2 was found to be higher than that of sample s- 1 and 3. [ABSTRACT FROM AUTHOR]

An overview of notable contributions of neutron scattering in the advancement of magnetic materials has been presented. A brief description of static neutron scattering techniques, viz., diffraction, depolarization, small angle scattering, and reflectivity, employed in the studies of advanced magnetic materials, is given. Apart from providing the up-to-date literature, this review highlights the importance of neutron scattering techniques in achieving microscopic as well as mesoscopic understanding of static magnetic properties of the following selective classes of advanced magnetic materials: (i) magnetocaloric materials, (ii) permanent magnets, (iii) multiferroic materials, (iv) spintronic materials, and (v) molecular magnetic materials. In the area of magnetocaloric materials, neutron diffraction studies have greatly improved the understanding of magneto-structural coupling by probing (i) atomic site distribution, (ii) evolution of structural phases and lattice parameters across the TC, and (iii) microscopic details of magnetic ordering in several potential magnetocaloric materials. Such an understanding is vital to enhance the magnetocaloric effect. Structural and magnetic investigations, employing neutron diffraction and allied techniques, have helped to improve the quality of permanent magnets by tailoring (understanding) structural phases, magnetic ordering, crystallinity, microstructure (texture), and anisotropy. The neutron diffraction studies of structural distortions/instabilities and magnetic ordering in multiferroic materials have improved the microscopic understanding of magnetoelectric coupling that allows one to control magnetic order by an electric field and electric order by a magnetic field in multiferroic materials. In the field of molecular magnetic materials, neutron diffraction studies have enhanced the understanding of (i) structural and magnetic ordering, (ii) short-range structural and magnetic correlations, (iii) spin density distribution and spin delocalization at molecular levels, and (iv) role of bridging ligands in propagating magnetic exchange interactions. The neutron diffraction studies have contributed towards the development of spintronics by bringing out (i) correlations between atomic site disorder and electronic spin polarization in full Heusler and half Heusler alloys, and (ii) microscopic origin of magnetic ordering in antiferromagnetic spintronics and other potential spintronic materials. Neutron depolarization, small angle neutron scattering, and neutron reflectometry techniques, on the other hand, have probed magnetism at mesoscopic length scales in such advanced magnetic materials. The derived understanding would be useful to exploit such materials for their practical applications as well as to set directions for future research in these areas. [ABSTRACT FROM AUTHOR]