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@INPROCEEDINGS{Rai:877253,
author = {Rai, Venus},
title = {{C}hiral {A}nomaly and {A}nomalous {H}all {E}ffect in
parent and {F}e doped {H}exagonal-{M}n3+δ{G}e {W}eyl
semimetals},
reportid = {FZJ-2020-02079},
year = {2020},
abstract = {Topological quantum materials have attracted enormous
attention since their discovery due to the observed
anomalous transport properties, which originate from the
non-zero Berry curvature. Mn3+δGe has gained special
attention because of its large anomalous transport effects
that persist starting from Néel temperature (365 K) down to
2 K. Due to the presence of very small in-plane
ferromagnetic component, chirality of magnetic structure can
be controlled easily by applying just a few hundred Oersted
(Oe) of magnetic field. Hexagonal - Mn3+δGe stabilizes in
the range of δ = 0.2 – 0.55. In order to understand the
involved quantum phenomena - Anomalous Hall effect (AHE) -
in such materials, it is also important to check the
stability of AHE with the variation of δ. Due to specific
mirror symmetry of the triangular antiferromagnetic
structure, AHE is expected to be observed when magnetic
field (B) is applied along x or y crystallographic axis. AHE
has been reported in the lower range of δ (= 0.22, 0.32
[Kiyohara et al. (2015)]), however the upper range of δ was
still unexplored. We have investigated samples with the
upper range of δ (~ 0.55) and AHE with very small Hall -
hysteresis (<200 Oe) was observed when the magnetic field
was applied along x or y crystallographic axis. The
magnitude of AHE in Mn3+0.55Ge is found to be more than
$25\%$ larger than the reported AHE for samples with δ =
0.22 – 0.32 (Kiyohara et al. (2015)). In addition to this,
Fe doping in Mn3.2Ge has also shown AHE of comparable
magnitude as observed in case of Mn3+0.55Ge. Despite being
considered as a Weyl semimetal, chiral anomaly (signature
for the presence of Weyl points) has not been observed in
Mn3+δGe yet. To establish the claim for the existence of
Weyl points in Mn3+δGe, transverse and longitudinal
magneto-resistance (MR) measurement was performed with the
magnetic field and electric current applied along several
combinations of x, y, z crystallographic axes. Angle
dependent measurements between the direction of current and
applied magnetic field has clearly shown the presence of
negative longitudinal MR as long as I||B. Negative
longitudinal MR is observed over a long range of magnetic
field and temperature. However, the monotonic increase in
magneto-resistace with angle (θ) between I and B is
observed for the intermediate magnetic field range (0.5 T- 2
T). This behavior is the signature of the chiral anomaly,
which evidently supports the claim for the presence of Weyl
points in Mn3+δGe compounds.},
month = {May},
date = {2020-05-28},
organization = {Institutsseminar des JCNS-2,
Forschungszentrum Jülich (Germany), 28
May 2020 - 28 May 2020},
subtyp = {Invited},
cin = {JCNS-2 / PGI-4 / JARA-FIT},
cid = {I:(DE-Juel1)JCNS-2-20110106 / I:(DE-Juel1)PGI-4-20110106 /
$I:(DE-82)080009_20140620$},
pnm = {144 - Controlling Collective States (POF3-144) / 524 -
Controlling Collective States (POF3-524) / 6212 - Quantum
Condensed Matter: Magnetism, Superconductivity (POF3-621) /
6213 - Materials and Processes for Energy and Transport
Technologies (POF3-621) / 6G4 - Jülich Centre for Neutron
Research (JCNS) (POF3-623)},
pid = {G:(DE-HGF)POF3-144 / G:(DE-HGF)POF3-524 /
G:(DE-HGF)POF3-6212 / G:(DE-HGF)POF3-6213 /
G:(DE-HGF)POF3-6G4},
typ = {PUB:(DE-HGF)31},
url = {https://juser.fz-juelich.de/record/877253},
}