2009/04/23 by G. Y. Wang, Wang, G. Y., K. H. Wong +3
Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.0904.3766
5 pages, 4 figures
arxiv created 2009/04/23 · arxiv updated 2009/12/01
A-site ordered manganites RBaMn2O6 (R = La, Pr, Nd, Sm) were synthesized and the oxygen isotope effect in them was studied. It was found that the substitution of 16O by 18O has caused increases in both the Neel temperature (TN) and the charge ordering temperature (TCO) and an decrease in the Curie temperature (TC). The isotope exponent is small on TC and TCO compared with that in A-site disordered manganites such as La1-xCaxMnO3, which may be caused by weaker electron-phonon coupling in A-site ordered ones. But the isotope exponent of TN is large for R = La. We didn't observe the large oxygen-isotope shift that occurs in NdBaMn2O6, where a multicritical point is believed to appear near R = Nd, and strong fluctuation due to the competition between ferromagnetic metal and charge ordering phase should be present.