Soft x-ray magnetic circular dichroism characterizations of spinel multiferroic ultra thin films/nano-crystals and 3d filled carbon nano tubes

by Pardeep Thakur, ESRF, Grenoble

Tuesday 11 May 2010, 11:00 → 12:30 Europe/Berlin

Bldg. 25b, room 109

X-ray magnetic circular dichroism (XMCD) is an element-, site-, and symmetry-selective spectroscopic technique that has potential to provide quantitative information on site occupancies in ferri- and ferro-magnetic materials. Moreover it is very powerful microprobe to demonstrate whether the spin polarization of the magnetic ions is consistent with the bulk magnetization of the samples and allow for distinguishing between contributions from localized ions (substitutional or interstitial) and metallic clusters. In this talk, some interesting results of spinel based multiferroic complex oxide systems will be shown. Spinel oxides exhibit a variety of interesting functional properties such as magnetoelectric multiferroic properties, thermoelectric property, colossal magnetoresistivity, spintronics, magnetic recording, etc., depending on the species and stoichiometry of cations occupying the A and B sites in AB₂O₄ type structure In the case of mixed Co-CuFe₂O₄ nano-crystals, we have provided the direct evidence of Cu ions to be ferromagnetic at room temperature (Cu L₃ edge XMCD hysteresis loops). I will also show our recent results of Fe(Co) filled carbon nano-tubes. Here, both Fe and Co ions are showing room temperature ferromagnetism through carbon-iron (cobalt) bonding in the system.