ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
A-site ordered PrBaMn2O6 manganites were obtained by a two-step synthesis process.The chemical composition, crystal structure, magnetic and magnetotransport properties have beeninvestigated with regard to the degree of ordering of the Pr3+ and Ba2+ cations. A-site disorderedPr0.50Ba0.50MnO3 has a cubic perovskite-like unit cell (SG = Pm3m , Z = 1), while the A-siteordered PrBaMn2O6 has a tetragonal unit cell (SG = P4/mmm, Z = 2). The A-site ordered state inPrBaMn2O6 remains stable on heating to 1300 0C in an oxidizing medium (P[O2] = 1 bar). Thecation ordering leads to a significant increase in the critical temperatures of phase transitions. Asiteordered PrBaMn2O6 is a metallic ferromagnet with the TC ~ 320 K, whereas TC of a fullydisordered sample is ∼ 140 K. The samples with intermediate degrees of ordering contain twomagnetic phases. Slightly below TC, all samples exhibit a metal–insulator transition and a peak ofthe magnetoresistance, amounting to approximately 10 % and 65 % in a magnetic field of 9 kOe forthe fully ordered PrBaMn2O6 and disordered Pr0.50Ba0.50MnO3, respectively. The results areinterpreted in terms of the degree of ordering of the Pr3+ and Ba2+ cations
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.128.187.pdf
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