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arXiv · 1608.04531

Finite-size scaling effect on N\'eel temperature of antiferromagnetic Cr$_2$O$_3$-(0001) films in an exchange-coupled heterostructure

Abstract

The scaling of antiferromagnetic ordering temperature of corundum-type chromia films have been investigated. N\'eel temperature $T_N$ was determined from the effect of perpendicular exchange-bias on the magnetization of a weakly-coupled adjacent ferromagnet. For a thick-film case, the validity of detection is confirmed by a susceptibility measurement. Detection of $T_N$ was possible down to 1-nm-thin chromia films. The scaling of ordering temperature with thickness was studied using different buffering materials, and compared with Monte-Carlo simulations. The spin-correlation length and the corresponding critical exponent were estimated, and they were consistent between experimental and simulation results. The spin-correlation length is an order of magnitude less than cubic antiferromagnets. We propose that the difference is from the change of number of exchange-coupling links in the two crystal systems.

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Satya Prakash Pati, Muftah Al-Mahdawi, Shujun Ye, Yohei Shiokawa, Tomohiro Nozaki, Masashi Sahashi. 2016-08-16. Finite-size scaling effect on N\'eel temperature of antiferromagnetic Cr$_2$O$_3$-(0001) films in an exchange-coupled heterostructure. https://doi.org/10.1103/physrevb.94.224417

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