Spin–glass transition in La{sub 0.75}Sr{sub 0.25}Mn{sub 0.5}Cr{sub 0.5−x}Al{sub x}O{sub 3−δ} perovskites
- Centre for Science at Extreme Conditions, University of Edinburgh, Erskine Building, Edinburgh EH9 3JZ (United Kingdom)
- School of Chemistry, University of St. Andrews, Fife KY16 9ST (United Kingdom)
Graphical abstract: In-phase and out-of-phase ac susceptibility measurements at the magnetic field 1000 Oe show the shifting of transition temperature with frequency (i.e. spin–glass transition) in La{sub 0.75}Sr{sub 0.25}Mn{sub 0.5}Cr{sub 0.3}Al{sub 0.2}O{sub 3−δ}. - Highlights: • Spin–glass transition at low temperature (around 50 K). • Al-doping decreases the antiferromagnetic transition temperature. • Ferromagnetic around room temperature. - Abstract: The structural and magnetic properties of the Al-doped La{sub 0.75}Sr{sub 0.25}Mn{sub 0.5}Cr{sub 0.5−x}Al{sub x}O{sub 3−δ} (x = 0.0, 0.1, 0.2, 0.3) were investigated by X-ray powder diffraction, neutron powder diffraction and magnetization measurements. Rietveld refinement of the diffraction data confirms that the compounds crystallize in rhombohedral symmetry (space group, R-3C). Unit cell volume decreases with increasing concentration of Al at the B-site. Upon cooling from room temperature, we have observed multiple magnetic phase transitions, i.e. paramagnetic (PM), ferromagnetic (FM), antiferromagnetic (AFM) and spin–glass (SG), in the samples. A low temperature magnetic hysteresis study demonstrates the presence of ferromagnetic domains for all compositions. The antiferromagnetic transition temperature decreases with the Al-doping AC susceptibility measurements at 97 Hz and 1 Oe show SG behaviors with a spin-freezing temperature close to 50 K for all samples. The in-phase ac susceptibility (χ{sup /}) decreases in magnitude and spin–glass transition (T{sub SG}) increase toward higher temperature with increasing frequency. The spin–glass behavior accompanied by the anomalous magnetic transitions is due to the competing interactions between FM and AFM. The results also shows that a part of the samples lose magnetic order to form a SG state accompanied by an AFM state at low temperature.
- OSTI ID:
- 22290458
- Journal Information:
- Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 7 Vol. 48; ISSN MRBUAC; ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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