12,949 research outputs found
Western colonial representations of the other: the case of Exotica Tibet
Alexandra David-Néel had influenced many belletrists as well as academics interested in Tibet by her travelogues and notes from journeys to Tibet, China, Nepal, Mongolia, and India. This text focuses on the image of her personality outlined in one of her most famous books, Voyage d'une Parisienne a Lhassa à Pied et en Mendiant de la Chine à l'Inde à Travers le Thibet, 1927. The image of a woman travelling to the forbidden mystical country, early anthropologist fascinated by Tibetan customs, and capable writer of novels pervades her books and gives an understanding of perspective oriental studies and early beginnings of Tibetan studies in Europe
Antiferromagnetism in EuCu2As2 and EuCu1.82Sb2 Single Crystals
Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb
self-flux, respectively. The crystallographic, magnetic, thermal and electronic
transport properties of the single crystals were investigated by
room-temperature x-ray diffraction (XRD), magnetic susceptibility \chi versus
temperature T, isothermal magnetization M versus magnetic field H, specific
heat Cp(T) and electrical resistivity \rho(T) measurements. EuCu2As2
crystallizes in the body-centered tetragonal ThCr2Si2-type structure (space
group I4/mmm), whereas EuCu2Sb2 crystallizes in the related primitive
tetragonal CaBe2Ge2-type structure (space group P4/nmm). The energy-dispersive
x-ray spectroscopy and XRD data for the EuCu2Sb2 crystals showed the presence
of vacancies on the Cu sites, yielding the actual composition EuCu1.82Sb2. The
\rho(T) and Cp(T) data reveal metallic character for both EuCu2As2 and
EuCu1.82Sb2. Antiferromagnetic (AFM) ordering is indicated from the \chi(T),
Cp(T), and \rho(T) data for both EuCu2As2 (T_N = 17.5 K) and EuCu1.82Sb2 (T_N =
5.1 K). In EuCu1.82Sb2, the ordered-state \chi(T) and M(H) data suggest either
a collinear A-type AFM ordering of Eu+2 spins S=7/2 or a planar noncollinear
AFM structure, with the ordered moments oriented in the tetragonal ab plane in
either case. This ordered-moment orientation for the A-type AFM is consistent
with calculations with magnetic dipole interactions. The anisotropic \chi(T)
and isothermal M(H) data for EuCu2As2, also containing Eu+2 spins S=7/2,
strongly deviate from the predictions of molecular field theory for collinear
AFM ordering and the AFM structure appears to be both noncollinear and
noncoplanar.Comment: 21 pages, 22 figures, 4 Table
Colonization with Chinese Characteristics: Politics of (In)Security in Xinjiang and Tibet
China as a victim rather than a proponent of modern colonialism is an essential myth that animates Chinese nationalism. The Chinese statist project of occupying, minoritizing and securitizing different ethno-national peoples of Central Asia such as Uyghurs and Tibetans, with their own claims to homelands, is a colonial project. Focusing on China’s securitized and militarized rule in Xinjiang and Tibet, the article will argue that the most appropriate lens through which this can be understood is neither nation-building, nor internal colonialism but modern colonialism. It argues that the representation of Uyghurs and Tibetans as sources of insecurity not only legitimizes state violence as a securitizing practice but also serves contemporary Chinese colonial goals
Metallic behavior induced by potassium doping of the trigonal antiferromagnetic insulator EuMn2As2
We report magnetic susceptibility \chi, isothermal magnetization M, heat
capacity C_p and electrical resistivity \rho measurements on undoped EuMn2As2
and K-doped Eu0.96K0.04Mn2As2 and Eu0.93K0.07Mn2As2 single crystals with the
trigonal CaAl2Si2-type structure as a function of temperature T and magnetic
field H. EuMn2As2 has an insulating ground state with an activation energy of
52 meV and exhibits antiferromagnetic (AFM) ordering of the Eu+2 spins S=7/2 at
T_N1 = 15 K from C_p(T) and \chi(T) data with a likely spin-reorientation
transition at T_N2 = 5.0 K. The Mn+2 3d5 spins-5/2 exhibit AFM ordering at T_N
= 142 K from all three types of measurements. The M(H) isotherm and \chi(T)
data indicate that the Eu AFM structure is both noncollinear and noncoplanar.
The AFM structure of the Mn spins is also unclear. A 4% substitution of K for
Eu in Eu0.96K0.04Mn2As2 is sufficient to induce a metallic ground state.
Evidence is found for a difference in the AFM structure of the Eu moments in
the metallic crystals from that of undoped EuMn2As2 versus both T and H. For
metallic Eu0.96K0.04Mn2As2 and Eu0.93K0.07Mn2As2, an anomalous S-shape T
dependence of \rho related to the Mn magnetism is found. Upon cooling from 200
K, \rho exhibits a strong negative curvature, reaches maximum positive slope at
the Mn T_N ~ 150 K, and then continues to decrease but more slowly below T_N.
This suggests that dynamic short-range AFM order of the Mn spins above the Mn
T_N strongly suppresses the resistivity, contrary to the conventional decrease
of \rho that is only observed upon cooling below T_N of an antiferromagnet.Comment: 21 pages, 22 figures, 4 Table
Physical properties of EuPd2As2 single crystals
The physical properties of self-flux grown EuPd2As2 single crystals have been
investigated by magnetization M, magnetic susceptibility chi, specific heat Cp,
and electrical resistivity rho measurements versus temperature T and magnetic
field H. The crystal structure was determined by powder x-ray diffraction
measurements, which confirmed the ThCr2Si2-type body-centered tetragonal
structure (space group I4/mmm) reported previously. The rho(T) data indicate
that state of EuPd2As2 is metallic. Long-range antiferromagnetic (AFM) ordering
is apparent from the chi(T), Cp(T), and rho(T) measurements. For H \parallel c
the chi(T) indicates two transitions at TN1 = 11.0 K and TN2 = 5.5 K, whereas
for H \perp c only one transition is observed at TN1 = 11.0 K. Between TN1 and
TN2 the anisotropic chi(T) data suggest a planar noncollinear AFM structure,
whereas at T < TN2 the chi(T) and M(H,T) data suggest a spin reorientation
transition in which equal numbers of spins cant in opposite directions out of
the ab plane. We estimate the critical field at 2 K at which all Eu moments
become aligned with the field to be about 22 T. The magnetic entropy at 25 K
estimated from the Cp(T) measurements is about smaller than expected,
possibly due to an inaccuracy in the lattice heat capacity contribution. An
upturn in rho at T < TN1 suggests superzone energy gap formation below TN1.
This behavior of rho(T < TN1) is not sensitive to applied magnetic fields up to
H = 12 T.Comment: 11 pages, 10 figures, 2 tables and 52 references; To appear in J.
Phys.: Condens. Matte
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