Ground-state ferrimagnetism and magneto-caloric effects in Nd<sub>2</sub>NiMnO<sub>6</sub>

Das, Ranjan; Yanda, Premakumar; Sundaresan, A.; Sarma, D. D.

doi:10.1088/2053-1591/ab4df2

“…The experimental study 27 on CaMnReCoO reports only magnetic susceptibility, and do not report dM/dT. However reported experimental dM/dT data for multiple magnetic ion containing Nd NiMnO double perovskite does exhibit such peak-shoulder structure 37 . Such two feature dM/dT curve is also seen for ferrimagnetic compound NiCr O 38 .…”

Section: Resultsmentioning

confidence: 97%

Understanding complex multiple sublattice magnetism in double double perovskites

Halder

¹

,

Das

²

,

Sanyal

³

et al. 2021

Sci Rep

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Understanding magnetism in multiple magnetic sublattice system, driven by the interplay of varied nature of magnetic exchanges, is on one hand challenging and on other hand intriguing. Motivated by the recent synthesis of AA$$^{\prime }$$ ′ BB$$^{\prime }$$ ′ O$$_6$$ 6 double double perovskites with multiple magnetic ions both at A- and B-sites, we investigate the mechanism of magnetic behavior in these interesting class of compounds. We find that the magnetism in such multiple sublattice compounds is governed by the interplay and delicate balance between two distinct mechanisms, (a) kinetic energy-driven multiple sublattice double exchange mechanism and (b) the conventional super-exchange mechanism. The derived spin Hamiltonian based on first-principles calculations is solved by classical Monte Carlo technique which reproduces the observed magnetic properties. Finally, the influence of off-stoichiometry, as in experimental samples, is discussed. Some of these double double perovskite compounds are found to possess large total magnetic moment and also are found to be half-metallic with reasonably high transition temperature, which raises the hope of future applications of these large magnetic moment half-metallic oxides in spintronics and memory devices.

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“…However reported experimental dM/dT data for multiple magnetic ion containing Nd 2 NiMnO 6 double perovskite does exhibit such two feature structure. [34] Such two feature dM/dT curve is also seen for ferrimagnetic compound NiCr 2 O 4 . [35] We notice with choice of DFT estimated value of D M n1−Co , the second feature appears around 200 K, very close to experimentally reported T C of 188 K. [27] Effect of Off-stoichiometry…”

Section: Monte Carlo Study Of the Spin Hamiltonianmentioning

confidence: 66%

Understanding Magnetism in Double Double Perovskites: A Complex Multiple Magnetic Sublattice System

Halder¹,

Das²,

Sanyal³

et al. 2021

Preprint

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Understanding magnetism in multiple magnetic sublattice system, driven by the interplay of varied nature of magnetic exchanges, is on one hand challenging and on other hand intriguing. Motivated by the recent synthesis of AA BB O 6 double double perovskites with multiple magnetic ions both at A-and B-sites, we investigate the mechanism of magnetic behavior in these interesting class of compounds. We find that the magnetism in such multiple sublattice compounds is governed by the interplay and delicate balance between two distinct mechanisms, a) kinetic energy-driven multiple sublattice double exchange mechanism and b) the conventional super-exchange mechanism. The derived spin Hamiltonian based on first-principles calculations is solved by classical Monte Carlo technique which reproduces the observed magnetic properties. Finally, the influence of off-stoichiometry, as in experimental samples, is discussed. Some of these double double perovskite compounds are found to possess large total magnetic moment and also are found to be halfmetallic, which raises the hope of future applications of these large magnetic moment half-metallic oxides in spintronics and memory devices.Perovskite structured ABO 3 transition metal oxides remained the holy grail of condensed matter physics due to wide range of fascinating properties exhibited by them, which includes properties like high temperature superconductivity, colossal magnetoresistance, half-metallicity etc. [1,2] With an aim to tailor properties further, one of the common route is cation substitution. Substitution and 1:1 ordering of cations in B sublattices in rock-salt arrangement give rise to A 2 BB O 6 double perovskites. [3][4][5][6] The topic of magnetism in transition metal oxides with two magnetic ions as in double perovskite structure has received significant attention. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] In this backdrop, it is an interesting issue to ask, what happens if the compounds involve even larger number of magnetic ions, i.e. more than two magnetic ions, as in double double perovskites. Due to the structural and compositional flexibility of the structure, perovskites can accommodate almost all of the elements of the periodic table, and also can support various possible coordination. In recent time double double perovskites of general formula AA 0.5 A 0.5 BB O 6 have been synthesized using high pressure and temperature, [23][24][25] combining columnar ordering at A sublattice and rock-salt ordering at B sublattice with five independent cation sites, A, A , A , B and B , hosting rare-earth or alkaline-earth ion at A site, 3d transition metals at A , A " and B sites, and 5d transition metal at B site. Use of high pressure is able to stabilize small magnetic transition-metal ions such as Mn 2+ at the A-sites of perovskites in place of large, nonmagnetic cations like Ca 2+ and Sr 2+ , with reduced coordination of tetrahedral (4) and square planar (4) instead of usual dodecahedral (12) coordination of A site. [26] This introduces a so...

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“…7(a)-(c) (Fig. 7(d)-(f)) 32 . In case of antialignment, external magnetic field can enforce an alignment and hence ∆S M also shows a sign reversal at sufficiently large magnetic field (see, for example, Fig.…”

Section: Resultsmentioning

confidence: 96%

“…Taken at face value the above observations seem to indicate that there is antiferromagnetic coupling between the R and Ni-Mn sublattice for R = Pr, Nd, and Sm, while this coupling is ferromagnetic for R = Gd, Tb, and Dy. [30][31][32] . However, recent DFT calculations of the exchange constants in Nd 2 NiMnO 6 have shown that the magnetic exchange between the Nd spin and the Ni-Mn sublattice is ferromagnetic ?…”

Section: Resultsmentioning

confidence: 99%

Rare-earth tuned magnetism and magnetocaloric effects in double perovskites $R_2$NiMnO$_6$

Ali,

Pasrija,

Sharma

et al. 2021

Preprint

0

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We present a comprehensive experimental study of magnetization and magnetocaloric effect (MCE) in double perovskite (DP) materials R2NiMnO6 with R = Pr, Nd, Sm, Gd, Tb, and Dy. While a paramagnetic to ferromagnetic transition, with TC in the range ∼ 100 − 200 K, is a common feature that can be attributed to the ordering of Mn 4+ and Ni 2+ magnetic moments, qualitatively distinct behavior depending on the choice of R is observed at low temperatures. These low-temperature anomalies in magnetization are also manifest in the change in magnetic entropy, −∆SM , whose sign depends on the choice of R. In order to understand these results, we present theoretical analysis based on mean-field approximation and Monte Carlo simulations on a minimal spin model. The model correctly captures the key features of the experimental observations.

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Ground-state ferrimagnetism and magneto-caloric effects in Nd₂NiMnO₆

Cited by 11 publications

References 27 publications

Understanding complex multiple sublattice magnetism in double double perovskites

Understanding complex multiple sublattice magnetism in double double perovskites

Understanding Magnetism in Double Double Perovskites: A Complex Multiple Magnetic Sublattice System

Rare-earth tuned magnetism and magnetocaloric effects in double perovskites $R_2$NiMnO$_6$

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Ground-state ferrimagnetism and magneto-caloric effects in Nd2NiMnO6

Cited by 11 publications

References 27 publications

Understanding complex multiple sublattice magnetism in double double perovskites

Understanding complex multiple sublattice magnetism in double double perovskites

Understanding Magnetism in Double Double Perovskites: A Complex Multiple Magnetic Sublattice System

Rare-earth tuned magnetism and magnetocaloric effects in double perovskites $R_2$NiMnO$_6$

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Ground-state ferrimagnetism and magneto-caloric effects in Nd₂NiMnO₆