Conţinutul numărului revistei |
Articolul precedent |
Articolul urmator |
123 0 |
SM ISO690:2012 MOSHNYAGA, Vasily T., BELENCHUK, Alexandr, HUHN, Sebastian, KALKERT, Christin, JUNGBAUER, Markus, LEBEDEV, Oleg, MERTEN, Sebastian, CHOI, Kwang Yong, LEMMENS, Peter, DAMASCHKE, Bernd, SAMWER, Konrad H.. Intrinsic antiferromagnetic coupling underlies colossal magnetoresistance effect: Role of correlated polarons. In: Physical Review B - Condensed Matter and Materials Physics, 2014, vol. 89, p. 0. ISSN 1098-0121. DOI: https://doi.org/10.1103/PhysRevB.89.024420 |
EXPORT metadate: Google Scholar Crossref CERIF DataCite Dublin Core |
Physical Review B - Condensed Matter and Materials Physics | |
Volumul 89 / 2014 / ISSN 1098-0121 /ISSNe 1550-235X | |
|
|
DOI:https://doi.org/10.1103/PhysRevB.89.024420 | |
Pag. 0-0 | |
Rezumat | |
A commonly believed picture of colossal magnetoresistance (CMR) effect is related to a first-order phase transition and electronic phase separation with coexisting ferromagnetic metallic and antiferromagnetic insulating phases. However, the underlying mechanism, i.e., the characteristic energy scale of the interacting phases and their spatial extent, is still under debate. Here we present experimental evidence on the existence of an effective antiferromagnetic coupling between the ferromagnetic nanodomains in epitaxial thin films of a classical CMR material (La1-yPry)0.67Ca0.33MnO3 with Pr doping, y = 0.375 and 0.4. This coupling yields to peculiar low-field CMR behavior with magnetic hysteresis and slow resistance relaxation, both induced by the magnetization reversal. The coercive field obeys a square-root temperature dependence for T TC and increases anomalously close to the phase transition. We modeled the magnetic structure within the phase-separation scenario as an assembly of single-domain ferromagnetic nanoparticles, antiferromagnetically coupled (pinned) by correlated Jahn-Teller polarons. The concentration of polarons increases drastically close to phase transition as indicated by the third harmonic of the electrical conductivity as well as Raman spectroscopy. |
|
Cuvinte-cheie perovskite, Magnetoresistance, Galvanomagnetic Effects |
|
|