Sunil Nair

Observation of three-dimensional Heisenberg-like ferromagnetism in single crystal La 0.875 Sr 0.125 MnO 3

We report measurements and analysis of the magnetic critical phenomena in a single crystal of

Formation of finite antiferromagnetic clusters and the effect of electronic phase separation in Pr0.5Ca0.5Mn0.975Al0.025O3

{\mathrm{La}}_{0.875}{\mathrm{Sr}}_{0.125}{\mathrm{MnO}}_{3}.

Probing a ferromagnetic critical regime using nonlinear susceptibility

The critical exponents associated with the ferromagnetic transition have been determined from ac susceptibility and dc magnetization data. Techniques like the Kouvel-Fischer plots, the modified Arrots plots, and the critical isotherm analysis were used for this purpose. The values of the exponents

Cu3Nb2O8: A Multiferroic with Chiral Coupling to the Crystal Structure

\ensuremath{\gamma},

Magnetism and superconductivity driven by identical 4f states in a heavy-fermion metal

\ensuremath{\beta},

Precursor State to Unconventional Superconductivity in CeIrIn5

and

Critical exponents and the correlation length in the manganite spin glass Eu0.5Ba0.5MnO3

\ensuremath{\delta}

Hall effect in heavy fermion metals

obtained are found to match very well with those predicted for the three-dimensional Heisenberg model. Our results are consistent with recent numerical calculations and suggest that though the double exchange interaction is driven by the motion of conduction electrons, the effective magnetic interaction near the transition is renormalized to a short range one.

Precursor state to superconductivity in CeIrIn5 : Unusual scaling of magnetotransport

We report the first experimental evidence of a magnetic phase arising due to the thermal blocking of antiferromagnetic clusters in the weakened charge and orbital ordered system Pr0.5Ca0.5Mn0.975Al0.025O3. The third order susceptibility (chi(3)) is used to differentiate this transition from a spin- or cluster-glass-like freezing mechanism. These clusters are found to be mesoscopic and robust to electronic phase separation which only enriches the antiphase domain walls with holes at the cost of the bulk, without changing the size of these clusters.