Antisite defects and magnetoresistance in Sr₂FeMoO₆double perovskite

Abstract

We report a detailed study of the magnetic and magnetotransport properties of Sr2FeMoO6 ceramics having a controlled concentration of antisite (AS) defects. It is found that a high-field differential susceptibility exists in all samples, which increases with AS. Similarly, a high-field magnetoresistivity develops and mimics the differential susceptibility. These observations suggest that antisite defects promote some magnetic frustration. High-resolution electron microscopy studies have allowed observation of the existence of antiphase boundary defects in the Sr2FeMoO6 structure.

Long-range order of Ni2+ and Mn4+ and ferromagnetism in multiferroic (Bi0.9La0.1)2NiMnO6 thin films

“…Notice that the diamagnetic substrate contribution has been subtracted from raw data. Our films have a magnetization M S ͑7 T, 10 K͒ Ϸ 3.5 B / f.u., in close agreement with data reported for bulk ͑Bi 0.9 La 0.1 ͒ 2 NiMnO 6 samples ͑M S Ϸ 3.6 B / f.u͒, which, we recall, do not saturate, either, even at 7 T and 5 K. 8 The presence of some antisite defects and antiphase boundaries, common defects in double perovskites structures, 21 may account for both the hardness to saturation and the accompanying reduced magnetization as found here. The magnetic remanence, as shown in Fig.…”

Direct Observation of Cationic Ordering in Double Perovskite Sr2FeReO6 Crystals

“…These oxides present antisite~AS! defects, in which cationic ordering in B-sites is frustrated by the occupation of B cations of B ' sites and vice versa; this situation is known to remarkably degrade the magnetic saturation, as well as the magnetoresistance~Balcells et al, 2001;García-Hernádez et al, 2001;Navarro et al, 2001!. So far, the conventional way to determine the presence of cationic ordering such as AS defects is to utilize a statistical tool~Lindén et al, 2000; Nakamura & Oikawa, 2003;Zajac et al, 2007! such as neutron diffraction, X-ray diffraction~XRD!, and Mossbauer spectroscopy, but the atomicscale observation of the local distribution of Fe/Re disordering cannot be predicted by such macroscopic analytical tools, even though the atomic-scale defective structures, such as antiphase boundary~APB!…”

Cerámicas magnetorresistivas. Progresos recientes: desde el entendimiento básico a las aplicaciones

“…Not only stoichiometry and sample purity are issues of major concern, but also the Fe/Mo ordering have been found to play a fundamental role on the sample magnetization and magnetoresistance [5,14]. In spite of these difficulties, the control of the synthesis protocol has rapidly progressed [5,14] and nowadays the magnetic properties of ceramic samples are well controlled and rather well understood. To illustrate the extreme sensitivity of transport properties to detailed oxygen treatment, we include in Fig.…”