Disordered ferromagnetism in Ho₂NiMnO₆double perovskite

Abstract

Magnetic and dielectric properties of the double perovskite HoNiMnO are reported. The compound is synthesized by nitrate route and is found to crystallize in monoclinic P2/n space group. Lattice parameters obtained by refining powder x-ray diffraction data are; a = 5.218(2) Å, b = 5.543(2) Å, c = 7.480(3) Å and the monoclinic angle is [Formula: see text](4). A phase transition is observed at [Formula: see text] K in the temperature-dependent magnetization curve, M(T). The inverse magnetic susceptibility, (1/[Formula: see text]) fits reasonably well with modified Curie-Weiss law by incorporating the paramagnetic response of Ho. 1/[Formula: see text] manifests as an upward deviation from ideal Curie-Weiss behaviour well above the ferromagnetic transition. Signs of inherent Griffiths phase pertaining to the Ni/Mn subsystem are visible when one subtracts the Ho paramagnetic contribution from total susceptibility and does the power-law analysis. The magnetic hysteresis at 2 K gives the maximum value of magnetization [Formula: see text] [Formula: see text]/f.u. at 50 kOe. Field-derivative of magnetization at 2 K shows discontinuities which indicates the existence of metamagnetic transitions in this compound. This needs to be probed further. Out of the two dielectric relaxations observed, the one at low temperature may be attributed to phononic frequencies and that at higher temperature may be due to Maxwell-Wagner relaxation. A correlation between magnetic and lattice degrees of freedom is plausible since the anomaly in dielectric constant coincides with T .

Enlarging the magnetocaloric operating window of the Dy2NiMnO6double perovskite by lanthanum doping

“…The new established interactions lead to a canted antiferromagnetic arrangement of Dy 3+ magnetic moments with respect to the Ni 2+ and Mn 4+ ferromagnetic-sublattices. A similar behaviour was recently observed in other R2NiMnO6 double perovskites 32,33 . This may explain the relatively low magnetic moment of Dy2NiMnO6 even under high magnetic fields as found at low temperatures.…”

Magnetocaloric properties of R2NiMnO6 (R=Pr, Nd, Tb, Ho and Y) double perovskite family

“…All the systems therefore are in pure phase according to X-ray diffraction results. The refined patterns are reported or will be published elsewhere [14,15,16,17].…”

Resonance Effect of Ionic Valences on the Structural and Magnetic Properties of Dy2NiMnO6 Induced by Nonmagnetic Al Ion Doping

“…Double perovskite oxides (A 2 NiMnO 6 , A = rare earth) have drawn great attention owning to the unique physical property and potential applications, including sensors, spintronics, large magnetocapacitance and magnetoresistance devices. Among them, La 2 NiMnO 6 is an attractive material with large magneto‐capacitance, magnetoresistance effect and super high ferromagnetic (FM) transition temperature T C1 ≈ 280 K .…”

“…The biphasic nature (Pbnm and R‐3c) exists in all the samples and the R‐3c phase displays the increasing trend with the increase of Cu content . Apart from the La 2 NiMnO 6 , researchers also focus on the investigation of other A 2 NiMnO 6 oxides simultaneously . For example, Jia et al reported the multiple magnetic phase transitions and magnetocaloric effect in A 2 NiMnO 6 ( A = Dy, Ho, and Er), including three magnetic phase transitions ( T R , T d–f , T C ) were observed for R 2 NiMnO 6 compounds corresponding to the rare earth ordering, 3d–4f exchange, and 3d metal ordering, respectively .…”