Structural, electronic, and magnetic properties of Sr2−xBaxFeMoO6(⩽x⩽2)

Abstract

Here we report on the investigation of structural, transport, and magnetic properties in double perovskite system, Sr2−xBaxFeMoO6(0⩽x⩽2). X-ray Diffraction analysis shows that the compounds form in single phase across the whole solid solution range. The Rietveld refinement of the x-ray data clearly indicates a structural transition from tetragonal (I4∕m) for x⩽0.6 to cubic (Fm3m) for x⩾1.6 with an orthorhombic (Fmmm) structure in the intermediate region (0.8⩽x⩽1.4). Magnetization studies show a regular increase in saturation magnetization from 2.0μB∕f.u.(x=0) to 3.0μB∕f.u.(x=2) with increasing Ba concentration. However, magnetization as well as electron-spin resonance (ESR) measurements confirmed a systematic decrease in the Curie temperatures from 420 K (x=0) to 310 K (x=2) with increasing x. Resistivity measurements carried out in zero magnetic field and for a field of 0.8 T reveal appreciably higher magnetoresistance for intermediate compositions in comparison to those at the ends.

Half-metallic double perovskites Sr2CrWO6 and Sr2FeReO6 materials for spintronics applications

“…[9][10][11][12][13][14] In particular, an ideal material with 100% spin-polarization is called a half-metal. 15 Such materials can be found in several materials classes; in classic inorganic oxides, such as magnetite (Fe 3 O 4 ) 16 and chromium dioxide (CrO 2 ), 17 in manganite perovskites as in (LaMnO 3 ) 18 and in Heusler alloy compounds as in (Co 2 Cr 1-x Fe x Al), 19,20 as well as in the group of double perovskites.…”

“…9,10 The large alkaline-earth metal atoms A 2+ occupied the body-centered site with 12-fold oxygen coordination in each unit cell. 11 In the ionic model of alkaline-earth metal based double perovskites, the pair of transition-metal ions are in the 8+ valence state, (BB') …”

Hallff--mettalllliic--fferriimagnettiic Sr2CrWO6 and Sr2FeReO6 matteriialls ffor room ttemperatture spiinttroniics:: Liinear muffffiin--ttiin orbiittall sttudiies

“…The large alkaline-earth metal A 2+ occupied the body-centered site with 12-fold oxygen coordination in each unit cell [3]. The long-range superexchange interactions between magnetic ions in complex perovskite A 2 BB'O 6 are in the form (-B -O -B' -) instead of double-exchange (-B -O -B -) in single perovskite ABO 3 [4], [5].…”

“…The corners of each perovskite unit cell are in turn occupied by different transition-metals B and B', have the mixed valence state (BB') 8+ ,with oxygen atoms located in between, forming alternate BO 6 and B'O 6 octahedra [1][2]. The large alkaline-earth metal A 2+ occupied the body-centered site with 12-fold oxygen coordination in each unit cell [3]. The long-range superexchange interactions between magnetic ions in complex perovskite A 2 BB'O 6 are in the form (-B -O -B' -) instead of double-exchange (-B -O -B -) in single perovskite ABO 3 [4], [5].…”

“…Complex perovskite oxides have the general chemical formula of A 2 BB'O 6 , crystalline in the rock-salt (Na + Cl -) structure with alternate perovskites ABO 3 and AB'O 3 along three crystallographical axes [1]. The corners of each perovskite unit cell are in turn occupied by different transition-metals B and B', have the mixed valence state (BB') 8+ ,with oxygen atoms located in between, forming alternate BO 6 and B'O 6 octahedra [1][2].…”