Exchange bias and magnetoresistance effects in La2-xSrxCoMnO6 (0.05 ≤ x ≤ 0.5)

Zero-field-cooled exchange bias effect in phase-segregated La2−xAxCoMnO6−δ (A=Ba,Ca,SrCoutrim1, Rigitano2, Macchiutti3 et al. 2019Phys. Rev. B599641View full textAdd to dashboardCite

“…SXRD measurements with E = 6500 eV were also performed for the Ba-, Ca-and Sr-doped compounds. For these samples the presence of two crystallographic phases is clear, as already proposed for resemblant compounds [30][31][32][33] . For LCCMO, as observed for LCMO, it was not found the weak reflections expected for P 2 1 /n space group.…”

Nonvolatile Control of the Electronic Properties of In2–xCrxO3 Semiconductor Films by Ferroelectric Polarization Charge

“…Combined with what we explained above, the negative MR is attributed to the formation of BMP caused by the overlap between the orbitals of electrons locally trapped by oxygen vacancy with the d shells of neighboring Cr dopants. − As a result, the BMPs increase with increasing Cr content, leading to the increase in the magnitude of negative MR. Similar phenomena were also observed and calculated in previous research studies [e.g., (In 0.98– x Co x Sn 0.02 ) 2 O 3 , ZnO:Cu, La 2– x Sr x CoMnO 6 , and Zn x Fe 3– x O 4 ]. ,,,, However, excessive doping may lead to antiferromagnetic coupling between nearest neighbor’s BMPs, thus suppresses negative MR. ,, Therefore, the magnitude of negative MR is slightly smaller as the Cr content increases from 8 to 11%. Upon the polarization switching from P r + to P r – , the MR changes from negative to positive and the influences of the FE field effect on the MR is greatly enhanced with increasing Cr content.…”

“…Similar phenomena were also observed and calculated in previous research studies [e.g., (In 0.98−x Co x Sn 0.02 ) 2 O 3 , ZnO:Cu, La 2−x Sr x CoMnO 6 , and Zn x Fe 3−x O 4 ]. 35,36,63,66,67 However, excessive doping may lead to antiferromagnetic coupling between nearest neighbor's BMPs, thus suppresses negative MR. 35,66,67 Therefore, the magnitude of negative MR is slightly smaller as the Cr content increases from 8 to 11%. Upon the polarization switching from P r + to P r − , the MR changes from negative to positive and the influences of the FE field effect on the MR is greatly enhanced with increasing Cr content.…”

Structural, transport, optical and electronic properties of Sr$_2$CoNbO$_6$ thin films

“…Interestingly, 50% substitution of B (Co) atoms by another transition metal atoms (B ) in these compounds gives an extra degree of freedom to tune the rock salt like ordering of their (B/B )O 6 octahedra, which can be controlled by the ionic radii and valence mismatch between them [26]. Thus, Co-based ordered perovskites (double perovskites with general formula A 2 BB O 6 ) give rise to the exotic magnetic, electronic and transport properties due to combined effects of valence and spin state transition of Co and flexibility in tuning the degree of B-site cationic ordering, where electronic band structure can be manipulated through the mechanical, chemical (doping) or mis-fit induced biaxial strain [27][28][29][30][31][32]. For example, electronic band gap has shown to be systematically suppressed with Sr concentration in La 2−x Sr x CoMnO 6 due to enhancement in the concentration of Co 3+ and hence evolution of new Co 3+ -O 2− -Mn 4+ conduction channel [30].…”

“…Thus, Co-based ordered perovskites (double perovskites with general formula A 2 BB O 6 ) give rise to the exotic magnetic, electronic and transport properties due to combined effects of valence and spin state transition of Co and flexibility in tuning the degree of B-site cationic ordering, where electronic band structure can be manipulated through the mechanical, chemical (doping) or mis-fit induced biaxial strain [27][28][29][30][31][32]. For example, electronic band gap has shown to be systematically suppressed with Sr concentration in La 2−x Sr x CoMnO 6 due to enhancement in the concentration of Co 3+ and hence evolution of new Co 3+ -O 2− -Mn 4+ conduction channel [30]. Hole doping in Ir t 2g band of La 2−x Sr x CoIrO 6 (0 x 2) for x 1.5 and in Co 3d band for x 1.5 also suppress electronic band gap [27].…”