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We report on the growth of single-crystal ErFeMnO 4 and its magnetization, resistivity, and dielectric dispersion behaviors for varying temperature and electric field. A clear bifurcation between the in-plane and out-of-plane M (T) curves is observed due to a paramagnetic-ferrimagnetic transition with a transition temperature of ∼301 K, which is higher than for other R Fe 2 O 4 or substituted compounds. Over a similar temperature range, sudden changes in both the relative permittivity and resistivity were also observed, indicating a strong connection between the magnetization, resistivity and dielectric properties. It can be concluded that the electron transfer between the Fe-site ions plays an important role in these behaviors. Finally, a large relative tunability of 75.9% for relative permittivity ε r and a net polarization P of about ∼408.7 μC/m2 were attained for a DC biased electric field E = 25 kV/m at 390 K, which are promising for the application of tunable ferroelectric devices. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic properties and magnetocaloric effect of C15 Laves phase TbMn1.8Fe0.2 were studied by magnetization and heat capacity measurements. The compound undergoes a second-order magnetic Tb–Tb sublattice ordering transition at its Curie temperature T C ∼80K, and a Fe–Fe ordering transition at ∼230K. A large magnetocaloric effect was observed around Tb–Tb ordering temperature with no obvious thermal and magnetic hysteresis loss. The maximum value of magnetic entropy change reaches 9.48Jkg−1 K−1 for a magnetic field change ΔH =5T. The corresponding maximum adiabatic temperature change is evaluated to be 3.5K with a wide effective temperature range. The obtained relative cooling power reaches 235, 607, and 869Jkg−1 for ΔH =2, 5 and 7T, respectively. These values indicate that TbMn1.8Fe0.2 could be a promising candidate for magnetic refrigeration. [Copyright &y& Elsevier]

Abstract: Systematic study on the magnetic properties has been performed for the Cr-doped Pr0.5Ca0.5Mn1− x Cr x O3 (x=0, 0.01, 0.03, 0.05, 0.07 and 0.10) system. For the samples with x=0.01 and 0.10, spin glass behavior is observed, which is resulted from different magnetic ground states. The present experiment establishes that the compound with x=0.01 shows a spin glass behavior in the background of an antiferromagnetic (AFM) matrix, while the spin glass behavior appears in the background of a ferromagnetic (FM) host phase for x=0.10. It is believed that the spin glass state accompanied by multiple magnetic transitions is resulted from the competing interaction between AFM matrix and FM phase induced by Cr-doping. The magnetic ground state in the manganites is strongly associated and very sensitive to Cr dopant. [Copyright &y& Elsevier]

A series of cadmium oxide samples (CdOs) were synthesized by thermal treatment method with various annealing temperatures (T A = 500 ℃ - 900 ℃). All samples crystallize in a pure cubic structure with Fm 3 ̅ m symmetry. The crystallite size, lattice parameter and volume change slightly with T A , and show an unexpected inflection point for the sample with T A = 800 ℃ (CdO-800), while the average particle size increases monotonically from ∼0.4 µm to ∼3.0 µm. Distinct ferromagnetic features accompanied by diamagnetic and/or paramagnetic phases were detected. The XPS data indicate the valence of cadmium and oxygen vacancy concentration varies with T A , which are responsible for the ferromagnetic origin in CdOs. CdO-800 shows the maximum magnetization, significant coercive force and residual magnetization. Oxygen vacancy plays a crucial role in the ferromagnetic performance, which can be effectively controlled by changing the sintering temperature. This work claims new characteristics for CdO besides optical and semi-conducting, which may be important in the preparation and possible applications for CdO dilute magnetic semiconductors. • The lattice parameter and grain size of CdO vary with annealing temperature. • The ferromagnetism of CdO stems from Cd and O vacancies. • This work claimed new characteristics for CdO besides optical and semi-conducting. [ABSTRACT FROM AUTHOR]

• Magnetic property of Heusler alloy Ni 43 Mn 46 Sn 9 Ge 2 with excess Mn was studied in detail. • The visible exchange bias, large coercivity and double-shifted hysteresis behaviors at low temperatures were observed and discussed. • Multiple magnetic phase transitions induced by magneto-structural coupling result in direct and inverse magnetocaloric effects. • Under µ 0 H = 5 T, the maximum value of magnetic entropy change (ΔS M max) reaches 22.88 J/kg.K, the refrigeration capacity (RC) reaches 125.89 J/kg. • ΔS M max increases at a rate of 4.58 J/kg.K per Tesla, while RC increases at a rate of 25.18 J/kg per Tesla. Multiple magnetic and structural phase transitions and magnetocaloric effect of Ni 43 Mn 46 Sn 9 Ge 2 Heusler alloy were detailedly investigated. The martensitic and inverse-martensitic transitions occur at temperatures slightly below room temperature, which induces a ferromagnetic - antiferromagnetic transition and large inverse magnetocaloric effect. A paramagnetic - ferromagnetic and antiferromagnetic - ferromagnetic transition was observed in high-temperature austenitic and low-temperature martensitic phase, respectively. The evident thermomagnetic irreversibility at low temperatures of the martensitic phase suggests a reentrant spin glass state, which originates from the frustration of the competing ferromagnetic and antiferromagnetic spins and results in the visible exchange bias, large coercivity and double-shifted hysteresis behaviors. A T - μ 0 H phase diagram was finally constructed. [ABSTRACT FROM AUTHOR]

Zn 0.97 − x Mg x Al 0.03 O ( x = 0 , 0.01 , 0.03 and 0.05 ) nanoparticles were prepared by hydrothermal growth, and their optical and magnetic properties were systematically studied by the X-ray diffraction (XRD), the UV-visible spectrophotometer, the infrared spectrometer and the physical properties measurement system (PPMS). These results showed that all the nanopowders had hexagonal wurtzite structures. With increasing the content of Mg, the strength of the (110) intensity peak increased. When Mg atoms were not incorporated into the Zn 0.97 Al 0.03 O lattice, the infrared light transmittance was higher than that of other groups of samples. In the UV range, the absorption decreased with the increase of the concentration of Mg. Mg doping weakened the magnetic property of the nanoparticles at room temperature. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves were separated with the decrease of temperature due to the pinning effect between the ferromagnetic domain and antiferromagnetic domain. [ABSTRACT FROM AUTHOR]