Enhanced ferromagnetism in H2O2-treated p-(Zn0.93Mn0.07)O layer

Abstract

Enhanced indirect ferromagnetic p-d exchange coupling of Mn in oxygen rich ZnO:Mn nanoparticles synthesized by wet chemical method J. Appl. Phys. 111, 033503 (2012); 10.1063/1.3679129High temperature carrier controlled ferromagnetism in alkali doped ZnO nanorods Enhanced ferromagnetism was observed from the H 2 O 2 -treated p-type ͑Zn 0.93 Mn 0.07 ͒O : As layer. Compared with the untreated sample, the H 2 O 2 -treated sample showed the enlarged ferromagnetic hysteresis loop with approximately two-times-increased spontaneous magnetization. And also, in comparison with the untreated sample ͑T C ϳ 280 K͒, the H 2 O 2 -treated sample exhibited to have the increased T C persisting up to above 350 K. These results were confirmed to originate from the enhanced p-d hybridization due to the decrease in negatively charged residual background carriers. This is because the increased effective g-factor resulting from the decrease in oxygen-related defects acting as native deep donors was observed from the H 2 O 2 -treated sample.

Room temperature ferromagnetism in Teflon due to carbon dangling bonds

“…Based on our experimental results, structural reconstruction may take place at temperature above 200 °C, which is in good agreement with results of Bunn et al 22 However, our experimental results indicate that the FM in Teflon is unstable when the samples are exposed to air. The adsorption of water molecules or formation of bonds between the under-coordinated C and H or OH is likely the reason for the elimination of FM.…”

“…We estimated g-factor to be 2.03 for the sample with a weak magnetization after annealing at 50 °C and 2.21 for the sample with a stronger saturation magnetization after annealing at 150 °C. The increase in g-factor with increasing magnetization might be related with the presence of a strong ferromagnetic resonance 21,22 . Temperature dependence of ESR analysis (Fig.…”

Transforming from paramagnetism to room temperature ferromagnetism in CuO by ball milling

“…As can be seen that Sample2 and Sample3 have obviously magnetic resonance signals, which are far away from 321 mT (which is the center magnetic field of the free electron). 20 This result indicates that both samples have obvious FM and the observed resonance signals are the ferromagnetic resonance signals. No ferromagnetic resonance signal is observed for Sample1, revealing the paramagnetism, which is corresponding to the result of SQUID.…”

Effects of curing temperature on physical properties of hydrothermally-grown yttrium-doped ZnO nanorods

“…However, bonding states of oxygen ions alter and depend on the curing temperature (Fig. 4) [21,22], natural oxygen atoms [22,23], and loosely-bound oxygen ions near the surface [24], respectively.…”