Room-Temperature Low-Field Colossal Magnetoresistance in Double-Perovskite Manganite

Abstract

The gigantic decrease of resistance by an applied magnetic field, which is often referred to as colossal magnetoresistance (CMR) 1-9 , has been an attracting phenomenon in strongly correlated electron systems. The discovery of CMR in manganese oxide compounds has developed the science of strong coupling among charge, orbital, and spin degrees of freedom. CMR is also attracting scientists from the viewpoint of possible applications to sensors, memories, and so on. However, no application using CMR effect has been achieved so far, partly because the CMR materials which satisfy all of the required conditions for the application, namely, high operating temperature, low operating magnetic field, and sharp resistive change, have not been discovered. Here we report a resistance change of more than two-orders of magnitude at a magnetic field lower than 2 T near 300 K in an A-site ordered NdBaMn 2 O 6 crystal. When temperature and a magnetic field sweep from insulating (metallic) phase to metallic (insulating) phase, the insulating (metallic) conduction changes to the metallic (insulating) conduction within 1 K and 0.5 T, respectively. The CMR is ascribed to the melting of the charge ordering. The entropy change which is estimated from the B-T phase diagram is smaller than what is expected for the charge and orbital ordering.The suppression of the entropy change is attributable to the loss of the short range ferromagnetic fluctuation of Mn spin moments, which an important key of the high temperature and low magnetic field CMR effect. arXiv:1811.07596v1 [cond-mat.str-el]

Structure and phase transitions in A -site ordered RBaMn2O6 ( R<

“…Such a low value of T N is at odds with previous neutron powder diffraction studies where the long-range AFM order was observed in the range 275-290 K [22,25]. In a later study the same authors, using a larger crystal, identified a series of superstructure peaks that were not compatible with the structure previously proposed and concluded that the NdBaMn 2 O 6 is isostructural with SmBaMn 2 O 6 and not compatible with an A-type magnetic ordering [26]. Therefore, the crystallographic and magnetic structures of NdBaMn 2 O 6 are now an open question.…”

“…According to Ref. [26], NdBaMn 2 O 6 could be isostructural to SmBaMn 2 O 6 . Our study does not support this statement.…”

“…This limit is sufficient to detect the superstructure peaks of SmBaMn 2 O 6 [38]. Reference [26] suggests that ( h 4 , k 4 , l ) t peaks are six orders of magnitude lower than the fundamental reflections. This would be below our resolution limit so we have explored this possibility.…”

Electro-Magnetic Behavior of Highly Correlated Fluorides KFeF3, KCoF3and KNiF3: A ComparativeAb-initioStudy of Cation Effect

“…Heterogeneous catalysts [30]. High dielectric permittivity (ε), ferroelectricity, Electronic correlations [31][32][33][34][35][36] of such 3d states are generally strong, they have a more local character and a tendency for insulating states or metal-insulator transitions [37][38], magneto-resistance colossal [39], high capacity memory [40]. As a new generation of promising photovoltaic devices, perovskite solar cells (PSCs) have rapidly evolved in efficiency from 3.8% in 2009 to 23.5% recently [41][42][43].…”

Magnetic Properties of La0.9A0.1MnO3 (A: Li, Na, K) Nanopowders and Nanoceramics

“…As the CMR effect is also often attributed to the Jahn-Teller (JT) effect [11], a parent compound of several important mixed-valence CMR manganite families, LaMnO 3 (LMO), is at the focus of intensive investigations [12,13]. Double perovskite-type manganites with a general formula AA BMnO 6 (where A and A are the rare earth or alkaline earth metals, and B is the d-block transition metals) also display a wide variety of interesting physical properties based on their compositional variations [14][15][16]. The usage of different dopants and changing the chemical make-up of manganites is focused on obtaining a material that can be used at room temperature and in a relatively low magnetic field.…”