Exposure of the Hidden Anti-Ferromagnetism in Para
Post# of 22456
Shou-Jyun Zou, Sheng-Tsung Wang, Ming-Fan Wu, Wen-Bin Jian, Shun-Jen Cheng
(Submitted on 1 May 2015)
We present theoretical and experimental investigations of the magnetism of paramagnetic semiconductor CdSe:Mn nanocrystals and propose an efficient approach to the exposure and analysis of the underlying anti-ferromagnetic interactions between magnetic ions therein. A key advance made here is the build-up of an analysis method with the exploitation of group theory technique that allows us to distinguish the anti-ferromagnetic interactions between aggregative Mn2+ ions from the overall pronounced paramagnetism of magnetic ion doped semiconductor nanocrystals. By using the method, we clearly reveal and identify the signatures of anti-ferromagnetism from the measured temperature dependent magnetisms, and furthermore determine the average number of Mn2+ ions and the fraction of aggregative ones in the measured CdSe:Mn nanocrystals.
http://arxiv.org/abs/1505.00126
Measurements. Magnetizations of Cd1-xMnxSe NCs were measured by a superconducting quantum interference device (SQUID), over the ranges of temperature from 2 to 200K and of magnetic field from 0 to 5 Tesla. The as-grown Cd1-xMnxSe NCs stabilized with capping agents of both TOP (trioctylphosphine) and oleic acid, whose magnetizations are much smaller than bulk Cd1-xMnxSe and are negligible. To extract the magnetization of CdSe:Mn NCs from the measured data, we subtracted only the sample holder background (mainly the capsule), which is about −1×10−6 emu at 0.1 Tesla.