TY - JOUR
T1 - An electron paramagnetic resonance and magnetically modulated microwave absorption characterization of thermochromic (Ba, Li)-Mn oxides
AU - Alvarez, G.
AU - Zamorano, R.
AU - Heiras, J.
AU - Castellanos, M.
AU - Valenzuela, R.
PY - 2007/9
Y1 - 2007/9
N2 - We report electron paramagnetic resonance (EPR) and magnetically modulated microwave absorption spectroscopy (MAMMAS) studies on powdered BaMnO3 and Li2MnO3 in the 77-300 K temperature range. The two oxides showed one single-line EPR spectra at room temperature. For Li2MnO3 the absorption line changed continuously with temperature, and showed a paramagnetic behavior in the whole temperature range. For BaMnO3 an additional signal was observed below ∼196 K; at low temperature (<135 K) the original signal has practically vanished. The changes in the g-factor, peak-to-peak linewidth (ΔHpp) and integrated intensity (IEPR) as a function of temperature are studied. The MAMMAS spectrum for Li2Mn03 showed a monotonic increase with temperature; this result confirmed its paramagnetic behavior. For BaMnO3 the MAMMAS signal exhibited a maximum at Tmax=139 K, approximately the temperature for the color change.
AB - We report electron paramagnetic resonance (EPR) and magnetically modulated microwave absorption spectroscopy (MAMMAS) studies on powdered BaMnO3 and Li2MnO3 in the 77-300 K temperature range. The two oxides showed one single-line EPR spectra at room temperature. For Li2MnO3 the absorption line changed continuously with temperature, and showed a paramagnetic behavior in the whole temperature range. For BaMnO3 an additional signal was observed below ∼196 K; at low temperature (<135 K) the original signal has practically vanished. The changes in the g-factor, peak-to-peak linewidth (ΔHpp) and integrated intensity (IEPR) as a function of temperature are studied. The MAMMAS spectrum for Li2Mn03 showed a monotonic increase with temperature; this result confirmed its paramagnetic behavior. For BaMnO3 the MAMMAS signal exhibited a maximum at Tmax=139 K, approximately the temperature for the color change.
KW - Electron paramagnetic resonance (EPR)
KW - Magnetic transition
KW - Manganite
UR - http://www.scopus.com/inward/record.url?scp=34250332670&partnerID=8YFLogxK
U2 - 10.1016/j.jmmm.2007.03.064
DO - 10.1016/j.jmmm.2007.03.064
M3 - Artículo
SN - 0304-8853
VL - 316
SP - e695-e698
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
IS - 2 SPEC. ISS.
ER -