Transport Properties and Magnetism of β-MnO2

1999 ◽  
Vol 602 ◽  
Author(s):  
H. Sato ◽  
T. Enoki ◽  
K. Wakiya ◽  
M. Isobe ◽  
Y. Ueda ◽  
...  

AbstractA comprehensive study of transport properties and magnetism on β-MnO2 reveals the strong coupling between the conduction electrons and the localized spins which are supposed to form a magnetic helix below TN ∼ 92 K. We also show the direct evidences of the helical magnetism by means of the measurements of the anisotropy in the magnetic susceptibility and the observation of x ray magnetic scatterings on a single crystal of β-MnO2. These results are consistent with proper-type helix model proposed by Yoshimori [J. Phys. Soc. Jpn. 14, p. 807 (1959)]. This model also qualitatively agrees with the anisotropy in magnetoresistance that appears below TN. The pitch of the magnetic helix is not commensurate to the lattice and it is slightly temperature dependent. The intensity of several Bragg peaks drastically changes at TN suggesting that the magnetic ordering is accompanied by a lattice distortion.

2013 ◽  
Vol 68 (11) ◽  
pp. 1191-1197 ◽  
Author(s):  
Bastian Reker ◽  
Bernard Chevalier ◽  
Oliver Niehaus ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen

The ternary stannides PrZnSn and NdZnSn were synthesized by induction-melting of the elements in sealed tantalum tubes. They were characterized by powder and single-crystal X-ray diffraction: YPtAs-type structure, P63=mmc, a = 455:4(1) and c = 1650:3(2) pm, wR2=0.0266, 297 F2 for PrZnSn and a = 453:7(1) and c = 1637:0(4) pm, wR2=0.1558, 234 F2 for NdZnSn with 12 variables per refinement. PrZnSn and NdZnSn are AlB2 superstructures with slightly puckered and ordered [Zn3Sn3] hexagons in AA´BB´ stacking sequence along the crystallographic c axis. Hydrogenation results in the new hexagonal hydrides PrZnSnH1:5 (a = 447:98(8) and c = 1707:5(5) pm) and NdZnSnH1:5 (a = 448:28(8) and c = 1689:8(2) pm). Filling of RE3Zn tetrahedra by hydrogen leads to anisotropic changes of the lattice parameters and a drastic flattening of the [Zn3Sn3] layers. Temperature-dependent magnetic susceptibility measurements show Curie-Weiss behavior for PrZnSn and NdZnSn with experimental magnetic moments close to the free-ion values of RE3+. Magnetic ordering is detected at 4.7 (PrZnSn) and 6:5 K (NdZnSn). Hydrogenation induces ferromagnetism with increased ordering temperatures of 12.0 (PrZnSnH1:5) and 14:5 K (NdZnSnH1:5).


2013 ◽  
Vol 68 (9) ◽  
pp. 971-978 ◽  
Author(s):  
Inga Schellenberg ◽  
Ute Ch. Rodewald ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen

The ternary antimonides RE4T7Sb6 (RE=Gd-Lu; T =Ru, Rh) have been synthesized from the elements by arc-melting and subsequent annealing in an induction furnace. The samples have been characterized by powder X-ray diffraction. Four structures were refined on the basis of single-crystal X-ray diffractometer data: U4Re7Si6 type, space group Im3m with a=862.9(2) pm, wR2=0.0296, 163 F2 values for Er4Ru7Sb6; a=864.1(1) pm, wR2=0.1423, 153 F2 values for Yb4Ru7Sb6; a=872.0(2) pm, wR2=0.0427, 172 F2 values for Tb4Rh7Sb6; and a=868.0(2) pm, wR2=0.0529, 154 F2 values for Er4Rh7Sb6, with 10 variables per refinement. The structures have T1@Sb6 octahedra and slightly distorted RE@T26Sb6 cuboctahedra as building units. The distorted cuboctahedra are condensed via all trapezoidal faces, and this network leaves octahedral voids for the T1 atoms. The ruthenium-based series of compounds was studied by temperature-dependent magnetic susceptibility measurements. Lu4Ru7Sb6 is Pauli-paramagnetic. The antimonides RE4Ru7Sb6 with RE=Dy, Ho, Er, and Tm show Curie-Weiss paramagnetism. Antiferromagnetic ordering occurs at 10.0(5), 5.1(5) and 4.0(5) K for Dy4Ru7Sb6, Ho4Ru7Sb6 and Er4Ru7Sb6, respectively, while Tm4Ru7Sb6 remains paramagnetic. Yb4Ru7Sb6 is an intermediate-valent compound with a reduced magnetic moment of 3.71(1) μB per Yb as compared to 4.54 μB for a free Yb3+ ion


2017 ◽  
Vol 72 (7) ◽  
pp. 511-515 ◽  
Author(s):  
Sebastian Stein ◽  
Lukas Heletta ◽  
Rainer Pöttgen

AbstractGdCuMg has been synthesized by induction-melting of the elements in a sealed niobium ampoule followed by annealing in a muffle furnace. The sample was studied by powder and single crystal X-ray diffraction: ZrNiAl type, P6̅2m (a=749.2(4), c=403.3(1) pm), wR2=0.0242, 315 F2 values and 15 variables. Temperature dependent magnetic susceptibility measurements have revealed an experimental magnetic moment of 8.54(1) μB per Gd atom. GdCuMg orders ferromagnetically below TC=82.2(5) K and based on the magnetization isotherms it can be classified as a soft ferromagnet.


2002 ◽  
Vol 01 (05n06) ◽  
pp. 455-459 ◽  
Author(s):  
JINKWON KIM ◽  
HAENGKYU CHO ◽  
AHKILESH K. GUPTA ◽  
JIN MOOK LIM ◽  
YOUNGKYU DO

New Mn12 single-molecule nanomagnets [ Mn 12 O 12( O 2 CCHCl 2)( H 2 O )4]· 2CH 2 Cl 2· H 2 O and [ Mn 12 O 12( O 2 CCHCl 2)( H 2 O )4]· 2CH 3 C 6 H 5· 4H 2 O and novel Mn18 complexes [ M 18 O 14( O 2 CR )18( hmp )4( hmpH )2( H 2 O )2] (R=Me, Et) have been synthesized and characterized by single crystal X-ray crystallography and dc- and ac-magnetic susceptibility measurements. Mn12 complexes show characteristic SMM properties, such as temperature-dependent out-of-phase ac-susceptibility. Mn18 does not show relaxation behaviors down to 2.0 K, but reveals magnetic anisotropy in reduced magnetization experiment.


2020 ◽  
Vol 75 (1-2) ◽  
pp. 73-82 ◽  
Author(s):  
Christian Paulsen ◽  
Theresa Block ◽  
Christopher Benndorf ◽  
Oliver Oeckler ◽  
Judith Bönnighausen ◽  
...  

AbstractThe gold-rich intermetallic compounds REAu4Cd2 (RE = La–Nd, Sm) were synthesized from the elements in sealed tantalum ampoules. Their characterization by X-ray powder and single crystal data confirmed the tetragonal YbAl4Mo2 type, space group I4/mmm. The basic building units are Au4 squares (278 pm Au–Au in CeAu4Cd2) and infinite linear cadmium chains (275 pm Cd–Cd in CeAu4Cd2). We exemplarily studied the solid solution CeAu4+xCd2−x for x = 0–1 up to CeAu5Cd. Electron diffraction patterns on a CeAu5Cd sample confirm the single crystal data. They give no hint for complete gold-cadmium ordering. Temperature-dependent magnetic susceptibility measurements of CeAu4Cd2, CeAu5Cd, PrAu4Cd2 and NdAu4Cd2 show stable trivalent rare earth ions and give no hint for magnetic ordering above 3 K.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nataliya L. Gulay ◽  
Maximilian Kai Reimann ◽  
Yaroslav M. Kalychak ◽  
Rainer Pöttgen

Abstract The rare earth-rich indides Tm4IrIn and Lu4PtIn were synthesized by reaction of the elements in sealed tantalum ampules in an induction furnace. Tm4IrIn (a = 1340.77(4) pm) and Lu4PtIn (a = 1338.0(1) pm) crystallize with the Gd4RhIn-type structure, space group F 4 ‾ 3 m $F‾{4}3m$ . The Lu4PtIn structure was refined from single crystal X-ray diffractometer data: wR = 0.0524, 517 F 2 values and 20 variables. The striking crystal chemical motif is the fcc packing of In4 tetrahedra with 318 pm In–In. The Lu4PtIn structure is closely related to the structures of Lu13Ni6In, Lu14Pd3In3 and Lu20Ir5In3 which all show icosahedral indium coordination and different condensation patterns that build up the indium substructure that consists of a dumbbell in Lu14Pd3In3 and a triangle in Lu20Ir5In3. The results of magnetic susceptibility measurements indicate Curie-Weiss paramagnetism for Tm4IrIn (7.76(1) µB per thulium atom) without magnetic ordering down to 2.5 K. Lu4PtIn is Pauli-paramagnetic.


2004 ◽  
Vol 848 ◽  
Author(s):  
Evan Lyle Thomas ◽  
Erin E. Erickson ◽  
Monica Moldovan ◽  
David P. Young ◽  
Julia Y. Chan

AbstractA new member of the LnMIn5 family, ErCoIn5, has been synthesized by a flux-growth method. The structure of ErCoIn5 was determined by single crystal X-ray diffraction. It crystallizes in the tetragonal space group P4/mmm, Z = 1, with lattice parameters a = 4.5400(4) and c = 7.3970(7) Å, and V = 152.46(2) Å3. Electrical resistivity data show metallic behavior. Magnetic susceptibility measurements show this compound to be antiferromagnetic with TN = 5.1 K. We compare these experimental results with those of LaCoIn5 in an effort to better understand the effect of the structural trends observed on the transport and magnetic properties.


1992 ◽  
Vol 271 ◽  
Author(s):  
Joseph E. Sunstrom ◽  
Susan M. Kauzlarich

ABSTRACTThe compounds La1−xBaxTiO3 (0 ≤ × ≤ 1) have been prepared by arc melting stoichiometric amounts of LaTiO3 and BaTiO3. Single phase samples can be made for the entire stoichiometry range. The polycrystalline samples have been characterized by thermal gravimetric analysis, X-ray powder diffraction, and temperature dependent magnetic susceptibility. This series of compounds has been studied as a possible candidate for an early transition metal superconductor.


CrystEngComm ◽  
2021 ◽  
Author(s):  
Wei Meng ◽  
Lin Du ◽  
Lin Sun ◽  
Lian Zhou ◽  
Xiaopeng Xuan ◽  
...  

One organic functional group was introduced to distinguish the four phenyl ring of tetraphenylethylene, and the In situ temperature-dependent crystal structures were determined to exhibit the conformation changes of tert-butyl...


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