K. Mukherjee

Bio: K. Mukherjee is an academic researcher from Indian Institute of Technology Mandi. The author has contributed to research in topics: Magnetization & Antiferromagnetism. The author has an hindex of 13, co-authored 92 publications receiving 640 citations. Previous affiliations of K. Mukherjee include Tata Institute of Fundamental Research.

Ferromagnetic ground state of the robust charge-ordered manganite Pr 0.5 Ca 0.5 Mn O 3 obtained by minimal Al substitution

Abstract: We show that minimal disturbance to the robust charge-ordered ${\mathrm{Pr}}_{0.5}{\mathrm{Ca}}_{0.5}\mathrm{Mn}{\mathrm{O}}_{3}$ by 2.5% Al substitution on the Mn site drives the system toward a ferromagnetic ground state. The history-dependent coexisting phases observed are explained as the outcome of a hindered first-order transition with glasslike arrest of kinetics resulting in irreversibility. Consistent with a simple phase diagram having a ferromagnetic ground state, it is experimentally shown that these coexisting phases are far from equilibrium.

Anomalous first-order transition in Nd0.5Sr0.5MnO3: an interplay between kinetic arrest and thermodynamic transitions

Abstract: A detailed investigation of the first-order antiferromagnetic insulator (AFI) to ferromagnetic metal (FMM) transition in Nd 0.5 Sr 0.5 MnO 3 is carried out by resistivity and magnetization measurements. These studies reveal several anomalous features of thermomagnetic irreversibility across the first-order transition. We show that these anomalous features cannot be explained in terms of the supercooling effect alone and the H-T diagram based on isothermal M-H or R-H measurements alone does not reflect the true nature of the first-order transition in this compound. Our investigations reveal glass-like arrest of kinetics at low temperature which plays a dominant role in the anomalous thermomagnetic irreversibility observed in this system. The interplay between kinetic arrest and supercooling is investigated by following novel paths in the H-T space. It is shown that coexisting FMM and AFI phases can be tuned in a number of ways at low temperature. These measurements also show that kinetic arrest temperature and supercooling temperature are anticorrelated, i.e. regions which are arrested at low temperature have higher supercooling temperature and vice versa.

Anomalous First Order Transition in $Nd{_{0.5}}Sr{_{0.5}}MnO{_{3}}$: An interplay between kinetic arrest and thermodynamic transitions

Abstract: A detailed investigation of the first order antiferromagnetic insulator (AFI) to ferromagnetic metal (FMM) transition in $Nd{_{0.5}}Sr{_{0.5}}MnO{_{3}}$ is carried out by resistivity and magnetization measurements. These studies reveal several anomalous features of thermomagnetic irreversibility across the first order transition. We show that these anomalous features can not be explained in terms of supercooling effect alone and H-T diagram based on isothermal MH or RH measurement alone do not reflect true nature of the first order transition in this compound. Our investigations reveal glass-like arrest of kinetics at low temperature which plays a dominant role in the anomalous thermomagnetic irreversibility observed in this system. The interplay between kinetic arrest and supercooling is investigated by following novel paths in the H-T space. It is shown that coexisting FMM and AFI phases can be tuned in a number of ways at low temperature. These measurements also show that kinetic arrest temperature and supercooling temperature are anti-correlated i.e. regions which are arrested at low temperature have higher supercooling temperature and vice versa.

Excess specific heat and evidence of zero-point entropy in magnetic glassy state of half-doped manganites

Abstract: We show that specific heat ${C}_{p}$ has non-Debye behavior for glassy states in half-doped manganites. Irrespective of the magnetic order or electronic states, these magnetic glasses have higher ${C}_{p}$ compared to their equilibrium counterparts. The excess ${C}_{p}$ contributed by the glassy state varies linearly with temperature similar to conventional glasses indicating tunneling in the two-level systems. These glassy states show signature of zero-point entropy. Magnetic glasses can be produced simply by different field cooling protocols and may be considered ideal magnetic counterpart of the conventional glass.

Handbook of Magnetic Materials

Abstract: Preface. Contents of volumes 1-6. 1. Magnetism in ultrathin transition metal films (U. Gradmann). 2. Energy band theory of metallic magnetism in the elements (V.L. Moruzzi, P.M. Marcus). 3. Density functional theory of the ground state magnetic properties of rare earths and actinides (M.S.S. Brooks, B. Johansson). 4. Diluted magnetic semiconductors (J. Kossut, W. Dobrowolski). 5. Magnetic properties of binary rare-earth 3d-transition-metal intermetallic compounds (J.J.M. Franse, R.J. Radwanski). 6. Neutron scattering on heavy fermion and valence fluctuation 4f-systems (M. Loewenhaupt, K.H. Fischer). Author index. Subject index. Materials index.

Introduction to Phase Transitions and Critical Phenomena

Abstract: H E Stanley Oxford: University Press 1971 pp xx + 308 price ?5 In the past fifteen years or so there has been a lot of experimental and theoretical work on the nature of critical phenomena in the neighbourhood of second order phase transitions. It has not been easy to get a good overall view of this work without digging through the rather complex original literature, although there are some good review articles covering particular aspects of the work.

Ferroelectricity in an Ising Chain Magnet

Abstract: We report discovery of collinear-magnetism-driven ferroelectricity in the Ising chain magnet Ca3Co2-xMn(x)O6 (x approximately 0.96). Neutron diffraction shows that Co2+ and Mn4+ ions alternating along the chains exhibit an up-up-down-down ( upward arrow upward arrow downward arrow downward arrow) magnetic order. The ferroelectricity results from the inversion symmetry breaking in the upward arrow upward arrow downward arrow downward arrow spin chain with an alternating charge order. Unlike in spiral magnetoelectrics where antisymmetric exchange coupling is active, the symmetry breaking in Ca3(Co,Mn)2O6 occurs through exchange striction associated with symmetric superexchange.