6,576 research outputs found
Nature of the glassy magnetic state in CuMnAl shape memory alloy
The magnetic ground state of the ferromagnetic shape memory alloy of nominal
composition CuMnAl was investigated. The sample
shows reentry of a glassy magnetic phase below the martensitic transition
temperature, which is found to have complex character with two distinct
anomalies in the temperature dependent ac susceptibility data. The sample
retains its glassy phase even below the second transition as evident from the
magnetic memory measurements in different protocols. Existence of two
transitions along with their observed nature suggest that the system can be
described by the mean field Heisenberg model of reentrant spin glass as
proposed by Gabay and Toulous. \cite{rsg-GT1} The sample provides a fascinating
example where a Gabay-Toulous type spin glass state is triggered by a first
order magneto-structural transition
Reentrant spin glass state in Mn doped Ni2MnSn shape memory alloy
The ground state properties of the ferromagnetic shape memory alloy of
nominal composition Ni2Mn1.36Sn0.64 have been studied by dc magnetization and
ac susceptibility measurements. Like few other Ni-Mn based alloys, this sample
exhibits exchange bias phenomenon. The observed exchange bias pinning was found
to originate right from the temperature where a step-like anomaly is present in
the zero-field-cooled magnetization data. The ac susceptibility study indicates
the onset of spin glass freezing near this step-like anomaly with clear
frequency shift. The sample can be identified as a reentrant spin glass with
both ferromagnetic and glassy phases coexisting together at low temperature at
least in the field-cooled state. The result provides us an comprehensive view
to identify the magnetic character of various Ni-Mn-based shape memory alloys
with competing magnetic interactions.Comment: 5 figure
Implications of lepton nonuniversality in the beauty sector
The phenomenon of CP violation in the standard model (SM) framework and the
decay dynamics have been established from the data obtained from the B
factories and so far we have not seen anything new. Nevertheless, there have
been instances of deviations in many measured observables in the flavor sector,
as far as the data and predictions are concerned. Here we will mention some
deviations obtained in measurements related to lepton universality, as seen
from the data, and try to understand their implications. To accommodate the
observed data we will consider a leptoquark model, which seems to be one
interesting model beyond the SM.Comment: 6 pages, 4 figures, talk given at BEACH 2016, George Mason
University, Fairfax, Virginia, USA, June 201
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