Studies on phase transition and phase coexistence - traversing T and H using liquid helium (2008)
Liquid helium is crucial to conveniently vary magnetic field (H) and temperature (T) giving access to a large region of (H, T) space; in stark contrast with the effort currently required to explore a...
Banerjee, A., Kumar, Kranti, Chaddah, P.
We show that Pr${_{0.5}}$Ca$_{0.5}$MnO${_3}$ with 2.5% Al substitution and La${_{0.5}}$Ca$_{0.5}$MnO${_3}$ (LCMO) exhibit qualitatively similar and visibly anomalous M-H curves at low temperature....
Recrystallization of glass: homogeneous vs. heterogeneous nucleation in La(0.5)Ca(0.5)MnO3 (2007)
Banerjee, A., Kumar, Kranti, Chaddah, P.
We probe through magnetization and resistivity measurements a kinetically arrested glass-like but long-range ordered magnetic state. The transformation kinetics of the magnetic field-temperature...
Chaddah, P., Kumar, Kranti, Banerjee, A.
Glass-like arrest of kinetics has been observed across many magnetic first-order transitions. By traversing the two control variable H-T space, tunable coexisting fractions of arrested and...
Field induced magnetic transition and metastability in Co substituted $Mn_{2}Sb$ (2007)
Kushwaha, Pallavi, Rawat, R, Chaddah, P
A detailed investigation of first order ferrimagnetic (FRI) to antiferromagnetic (AFM) transition in Co (15%) doped $Mn_2Sb$ is carried out. These measurements demonstrate anomalous thermomagnetic...
Two-phase coexistence is tunable and is not the equilibrium state in half-doped manganites (2007)
We discuss our very interesting experimental observation that the low-temperature two-phase coexistence in half-doped manganites is multi-valued (at any field) in that we can tune the coexisting...
Coexisting tuneable fractions of glassy and equilibrium long-range-order phases in manganites (2006)
Banerjee, A., Pramanik, A. K., Kumar, Kranti, Chaddah, P.
Antiferromagnetic-insulating(AF-I) and the ferromagnetic-metallic(FM-M) phases coexist in various half-doped manganites over a range of temperature and magnetic field, and this is often believed to...
Rawat, R., Mukherjee, K., Kumar, Kranti, Banerjee, A., Chaddah, P.
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...
Banerjee, A., Mukherjee, K., Kumar, Kranti, Chaddah, P.
We show that minimal disturbance to the robust charge ordered Pr(0.5)Ca(0.5)MnO(3) by 2.5% Al substitution on Mn-site drives the system towards ferromagnetic ground state. The history-dependent...
Kumar, Kranti, Pramanik, A. K., Banerjee, A., Chaddah, P., Roy, S. B., Park, S., ...
Coexisting ferromagnetic and antiferromagnetic phases over a range of temperature as well as magnetic field have been reported in many materials of current interest, showing disorder-broadened 1st...
Studies on Magnetic-field induced first-order transitions (2006)
We shall discuss magnetization and transport measurements in materials exhibiting a broad first-order transition. The phase transitions would be caused by varying magnetic field as well as by varying...
Chaddah, P., Banerjee, A., Roy, S. B.
Coexisting ferromagnetic (FM) and antiferromagnetic (AFM) phases over a range of temperature (T) and magnetic field (H), have been reported in many materials. The 1st order FM-AFM transition is...
Rai, S., Tiwari, M. K., Lodha, G. S., Modi, M. H., Chattopadhyay, M. K., Majumdar, S., ...
We report a detailed study of surface and interface properties of pulsed-laser deposited NiMnSb films on Si (100) substrate as a function of film thickness. As the thickness of films is reduced below...
Chandra, L. S. Sharath, Mukherjee, Kaustav, Ganesan, V., Banerjee, A., Chaddah, P., Chattopadhyay, M. K., ...
Field variation of heat capacity at fixed temperatures is investigated to identify the origin of the field induced first order phase transition in polycrystalline Ce(Fe$_{0.094}$Al$_{0.04}$)$_2$...
Chattopadhyay, M. K., Roy, S. B., Chaddah, P.
We present results of dc magnetization and magnetic relaxation study showing the kinetic arrest of a first order ferromagnetic to antiferromagnetic transition in Ce(Fe$_{0.96}$Ru$_{0.04}$)$_2$. This...
Unusual transport properties of ferromagnetic Heusler alloy Co$_2$TiSn (2005)
Majumdar, S., Chattopadhyay, M. K., Sharma, V. K., Sokhey, K. J. S., Roy, S. B., Chaddah, P.
We report results of magnetization, zero field resistivity and magnetoresistance measurements in ferromagnetic Heusler alloy Co$_2$TiSn. There is a striking change in the character of electron...
Roy, S. B., Chattopadhyay, M. K., Chaddah, P., Nigam, A. K.
Very sharp magnetization step is observed across the field induced antiferromagnetic to ferromagnetic transition in various doped-CeFe$_2$ alloys, when the measurement is performed below 5K. In the...
First order magnetic transition in CeFe$_2$ alloys: Phase-coexistence and metastability (2003)
Roy, S. B., Perkins, G. K., Chattopadhyay, M. K., Nigam, A. K., Sokhey, K. J. S., Chaddah, P., ...
First order ferromagnetic (FM) to antiferromagnetic (AFM) phase transition in doped-CeFe$_2$ alloys is studied with micro-Hall probe technique. Clear visual evidence of magnetic phase-coexistence on...
Relaxation under Supercooling of the Disordered Vortex State in Doped CeRu2 Alloy (2003)
Chattopadhyay, M. K., Sokhey, K. J. S., Roy, S. B., Chaddah, P.
Relaxation in magnetisation of metastable states is reported. The states are prepared by supercooling a Ce(Ru, 5% Nd)2 alloy sample to different extents through similar paths in the H-T space, and...
Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn_2Ge_2 (2002)
Roy, S. B., Chaudhary, S., Chattopadhyay, M. K., Chaddah, P., Sampathkumaran, E. V.
We present results of magnetization measurements showing that the magnetic response of the antiferromagnetic state of SmMn_2Ge_2 depends on the path used in the field(H)-temperature(T) phase space to...
Resistivity and thermoelectric power measurements on CeFe$_2$ and its pseudobinaries (2002)
Chattopadhyay, M. K., Manekar, Meghmalhar, Singh, Kanwal Jeet, Chaudhary, Sujeet, Roy, S. B., Chaddah, P.
Resistivity and thermoelectric power (TEP) measurements on CeFe$_2$ and two of its pseudo-binaries Ce(Fe, 5% Ir)$_2$ and Ce(Fe, 7% Ru)$_2$ between 78K and 275K are reported. The resistivity data are...
Thermomagnetic history effects in SmMn$_2$Ge$_2$ (2002)
Chaudhary, Sujeet, Chattopadhyay, M. K., Singh, Kanwal Jeet, Roy, S. B., Chaddah, P., Sampathkumaran, E. V.
The intermetallic compound SmMn$_2$Ge$_2$, displaying multiple magnetic phase transitions, is being investigated in detail for its magnetization behavior near the 145 K first order ferromagnetic to...
Singh, Kanwal Jeet, Chaudhary, Sujeet, Chattopadhyay, M. K., Manekar, M. A., Roy, S. B., Chaddah, P.
The magnetotransport behaviour is investigated in detail across the first order magnetic phase transition from ferromagnetic to antiferromagnetic state in polycrystalline...
Metastabilities across disorder-broadened first-order transitions (2001)
We discuss first-order phase transitions that are broadened by disorder, but still remain first order on the local mesoscopic level. Using vortex-matter as our paradigm, we argue that phase...
Roy, S. B., Radzyner, Y., Giller, D., Wolfus, Y., Shaulov, A., Chaddah, P., ...
We highlight interesting thermomagnetic history effects across the transition line between the (quasi) ordered and disordered vortex states in single crystal YBa$_2$Cu$_3$O$_{7-\delta}$, and argue...
A recent paper [Physical Review {\bf B 64} 014508 (2001)] claims to present an exact method to extract the critical current density J$_C$ from the M-H hysteresis curve. We show that this claim...
Manekar, M. A., Chaudhary, S., Chattopadhyay, M. K., Singh, K. J., Roy, S. B., Chaddah, P.
Taking the pseudobinary C15 Laves phase compound Ce(Fe$_{0.96}$Al$_{0.04}$)$_2$ as a paradigm for studying a ferromagnetic to antiferromagnetic phase transition, we present interesting thermomagnetic...
Manekar, M. A., Chaudhary, S., Chattopadhyay, M. K., Singh, K. J., Roy, S. B., Chaddah, P.
Results of dc magnetization study are presented showing interesting thermomagnetic history effects across the antiferromagnetic to ferromagnetic transition in Ce(Fe$_{0.96}$Al$_{0.04})_2$....
Peak effect in the vortex state of V$_3$Si: a study of history dependence (2000)
Chaudhary, Sujeet, Rajarajan, A. K., Singh, Kanwal Jeet, Roy, S. B., Chaddah, P.
We present results of transport properties measurement on a single crystal of V$_3$Si showing distinct signature of peak-effect in its vortex state. The field variation of the electrical resistance...
First order metamagnetic transition in CeFe$_2$ based pseudobinary alloys (2000)
Manekar, Meghmalhar, Chaudhary, Sujeet, Chattopadhyay, M. K., Singh, Kanwal Jeet, Roy, S. B., Chaddah, P.
We present results of dc magnetisation study showing that the low temperature antiferromagnetic state in various CeFe$_2$-based pseudobinary alloys can be transformed into ferromagnetic state through...
We present a model in which metastable supercooled phase and stable equilibrium phase of vortex matter coexist in different regions of a sample. Minor hysteresis loops are calculated with the simple...
Manekar, Meghmalhar, Roy, S. B., Chaddah, P.
We present results of ac susceptibility measurements highlighting the presence of thermal hysteresis and phase coexistence across the ferro-to antiferromagnetic transition in various CeFe$_2$ based...
Vortex Matter and its Phase Transitions (2000)
The mixed state of type II superconductors has magnetic flux penetrating the sample in the form of vortices, with each vortex carrying an identical quantum of flux. These vortices generally form a...
Peak effect in CeRu$_2$:history dependence and supercooling (2000)
Roy, S. B., Chaddah, P., Chaudhary, Sujeet
We present experimental results on single crystal CeRu$_2$ showing that the extent of history dependence of peak-effect depends on the path followed in the space of field (H) and temperature (T). The...
Chaudhary, Sujeet, Rajarajan, A. K., Singh, Kanwal Jeet, Roy, S. B., Chaddah, P.
We present results of transport measurements showing distinct path dependence of the electrical resistance in the superconducting vortex state of single crystal samples of CeRu$_2$ and V$_3$Si....
Metastabilities in vortex matter (1999)
We extend the classical theory for supercooling across first order phase transitions to the case when both density and temperature are control variables. The observable region of metastability then...
Supercooling across first-order phase transitions in vortex matter (1999)
Hysteresis in cycling through first-order phase transitions in vortex matter, akin to the well-studied phenomenon of supercooling of water, has been discussed in literature. Hysteresis can be seen...