Ferromagnetic ordering in nanostructured Mn-doped InP

We report the observation of ferromagnetic ordering at 25 K in a diluted magnetic semiconductor (DMS) nanoparticle system: In0.9 Mn0.1 P, sized 3 nm. These particles were synthesized using a novel nanochemical technique without using any external surfactant. Structural and elemental characterizations established the occurrence of the zinc-blende phase of the DMS without any separate or induced impurity phase. A robust onset of ferromagnetic order is observed in magnetization measurements at around 25 K with blocked state behavior below 15 K characteristic of magnetic nanoparticles. The system shows strong frequency dependence of the susceptibility, similar to the behavior observed for spin glasses. Reversible transverse susceptibility experiments done using a resonant radio-frequency (rf) method reveal a strong temperature-dependent effective anisotropy.