Evidence of disorder induced magnetic spin glass phase in Sr2FeMoO6 double perovskite

Abstract

The present work described the disorder induced magnetic properties of Sr2FeMoO6 (SFMO) samples. The crystal structure and magnetic order of SFMO samples with nanosized grains were studied using x-ray diffraction spectrum, scanning electron microscope morphology, and magnetic measurements. Thermal annealing of as prepared chemical routed materials showed an increase in grain size and in the magnetic moment per formula unit. A small decrease in magnetic moment was noted at higher annealing temperature. At the same time, the ac susceptibility measurement indicated the presence of a magnetic spin glass phase in the material, coexisting with the ferromagnetic matrix. The observation of the magnetic glassy phase confirmed the presence of intrinsic disorder in the lattice structure of SFMO. The signature of intrinsic disorder in the samples, irrespective of annealing temperatures, is also realized from the splitting of temperature dependent field cooled and zero field cooled magnetization curves. Such magnetic splitting in the temperature dependence of magnetization curves is suppressed at a higher magnetic field. A careful analysis of the temperature and field dependent magnetization data provided more insight on the grain size dependent disorder in the double perovskite structure.

Effects of different annealing atmospheres on magnetic properties in La2CoMnO6 single crystals

“…For instance, Sr 2 FeMoO 6 [1] and Sr 2 FeReO 6 [2,3] with highly ordered transition metal ions exhibit a tunneling-type magnetoresistance at room temperature, while disordered Sr 2 FeMoO 6 shows spin-glass behavior [4]. Another example can be found in the double-perovskite A2MReO6 (A ¼ Sr, Ca; M ¼ Mg, Sc, Cr, Mn, Fe, Co, Ni, Zn) whose structural and electronic properties depend on the mixed-valent states [5].…”

Phase Transformations and Magnetic State in the Nanoscale Metal-Oxide Sr$_{2}$FeMoO$_{6-\delta}$ Compounds

“…В связи с этим в последнее время учёные все больше начинают прибегать к золь-гель-технологии, обладающей большими потенциальными возможностями, позволяющей синтезировать наноразмерный двойной перовскит при сравнительно невысокой температуре и меньших затратах времени [13,14,21]. Интерес к данному методу синтеза обусловлен и тем, что с помощью золь-гель-технологии по-является возможность разработки новых композиционных матери-алов типа Sr 2 FeMoO 6 (сверхпроводник, полупроводник, диэлек-трик) для спинтронных устройств нового поколения.…”

Interplay between phase formation mechanisms and magnetism in the Sr2FeMoO6–δ metal‐oxide compound

“…Strong interplay between the electron spins, charges, and crystal lattice induces different electrical (conducting, semiconducting or isolating) and magnetic (para -(PM), antiferro-(AF), superparamagnetic (SPM) and ferrimagnetic (FRM)) states [5][6][7][8]. Possessing notable advantages as compared to manganites, complex transition metal oxides A 2 BB´O 6 are very promising for spintronic devices [8,9].…”

“…Strong interplay between the electron spins, charges, and crystal lattice induces different electrical (conducting, semiconducting or isolating) and magnetic (para -(PM), antiferro-(AF), superparamagnetic (SPM) and ferrimagnetic (FRM)) states [5][6][7][8]. Possessing notable advantages as compared to manganites, complex transition metal oxides A 2 BB´O 6 are very promising for spintronic devices [8,9]. In particular, strontium ferromolybdate Sr 2 FeMoO 6-δ (SFMO) possesses high negative magnetoresistance (MR) of about 30% at 4.2 K, high Curie temperature of 400-430 K, nearly 100% spin polarisation, temperature stability of giant magnetoresistance (GMR), a chemical resistivity to reduction atmosphere and, therefore, reproducible magneto-transport characteristics [5,8,10].…”

“…Possessing notable advantages as compared to manganites, complex transition metal oxides A 2 BB´O 6 are very promising for spintronic devices [8,9]. In particular, strontium ferromolybdate Sr 2 FeMoO 6-δ (SFMO) possesses high negative magnetoresistance (MR) of about 30% at 4.2 K, high Curie temperature of 400-430 K, nearly 100% spin polarisation, temperature stability of giant magnetoresistance (GMR), a chemical resistivity to reduction atmosphere and, therefore, reproducible magneto-transport characteristics [5,8,10]. Owing to a non-parallel arrangement of spins of the Fe 3+ (3d 5 ; S = 5/2) and Mo 5+ (4d 1 ; S = 1/2) cations that form an angle of 120°, generated ferrimagnetic structure determines the half-metallic state of the complex oxide with two separated conduction bands [11,12].…”