High temperature spin-freezing transition in pyrochlore Eu2Ti2O7: A new observation from ac-susceptibility

We report the structure and physical properties of two quasi-two-dimensional triangular antiferromagnetic materials, Co0.66Al2Se3.53 and Ni0.61Al2Se3.55, which show highly magnetically frustrated characters. Powder X-ray diffractions demonstrate that Co0.66Al2Se3.53 and Ni0.61Al2Se3.55 possess identical space group of P-3m1 with lattice parameters a = 3.8089(1) Å, c = 12.676(1) Å and a = 3.7880(1) Å, c = 12.650(1) Å, respectively. Analyzing the susceptibility data of Co0.66Al2Se3.53 reveal a Curie Weiss temperature of −216 K, and a spin-freezing transition temperature of 4.5 K, giving a frustration index f = −θcw/Tf ≈ 48. Ni0.61Al2Se3.55 possesses an effective moment of 2.38 µB, a Curie–Weiss temperature of −62 K with no sign of spin-freezing transition down to 2 K. The AC susceptibility data of Co0.66Al2Se3.53 suggest a spin glass-like transition, but no intersite mixing between Co2+ and Al3+ was observed from the X-ray photoelectron spectroscopy measurements.

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Frequency response of AC susceptibility in high temperature superconductors

Solid State Communications ◽

10.1016/j.ssc.2005.03.069 ◽

2005 ◽

Vol 135 (3) ◽

pp. 203-207 ◽

Cited By ~ 12

Author(s):

S.L. Liu ◽

G.J. Wu ◽

X.B. Xu ◽

J. Wu ◽

H.M. Shao ◽

...

Keyword(s):

High Temperature ◽

Frequency Response ◽

Ac Susceptibility ◽

High Temperature Superconductors

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Comment on “Field dependence of the transverse spin freezing transition”

Physical Review B ◽

10.1103/physrevb.65.176401 ◽

2002 ◽

Vol 65 (17) ◽

Cited By ~ 1

Author(s):

D. Kaptás ◽

L. F. Kiss ◽

J. Balogh ◽

I. Vincze

Keyword(s):

Field Dependence ◽

Transverse Spin ◽

Freezing Transition ◽

Spin Freezing

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Ac Susceptibility of High-Temperature Ceramic Superconductors: Critical State and Creep at Grain Boundaries and in Grains

Advances in Superconductivity III ◽

10.1007/978-4-431-68141-0_130 ◽

1991 ◽

pp. 583-586 ◽

Cited By ~ 4

Author(s):

K.-H. Müller ◽

M. Nikolo ◽

N. Savvides ◽

R. Driver

Keyword(s):

High Temperature ◽

Grain Boundaries ◽

Critical State ◽

Ac Susceptibility ◽

Ceramic Superconductors

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AC susceptibility of high temperature superconductors in a critical state model

Physica C Superconductivity ◽

10.1016/0921-4534(89)90143-3 ◽

1989 ◽

Vol 159 (6) ◽

pp. 717-726 ◽

Cited By ~ 332

Author(s):

K.-H. Müller

Keyword(s):

High Temperature ◽

Critical State ◽

Ac Susceptibility ◽

High Temperature Superconductors ◽

Critical State Model ◽

State Model

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Crystal Growth, Structure, and Incoherent Metallic Behaviour of FeCrAs

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.170.276 ◽

2011 ◽

Vol 170 ◽

pp. 276-281 ◽

Cited By ~ 7

Author(s):

Wen Long Wu ◽

Alix McCollam ◽

Ian P. Swainson ◽

Stephen R. Julian

Keyword(s):

High Temperature ◽

High Temperature Superconductivity ◽

High Temperature Superconductors ◽

Magnetic Hysteresis ◽

Freezing Temperature ◽

Growth Structure ◽

Preparation Conditions ◽

Scattering Rate ◽

Spin Freezing ◽

Low Levels

There is growing interest in a possible connection between incoherent metallic conduction and high temperature superconductivity, that is exemplified by the behaviour of the parent compounds of the new iron-pnictide high-temperature superconductors. We have recently discovered very incoherent behaviour in the non-superconducting arsenide, FeCrAs. This material shows a non-metallic resistivity that rises with decreasing temperature without saturation or a gap, over three decades of temperature, from 80 mK to 800 K. We briefly review this behaviour, and address the question of disorder: how to test for the presence of disorder in a system where the scattering rate inferred from the resistivity is highly abnormal, and how to produce single crystals with low levels of disorder. Our discussion will focus on magnetic properties. FeCrAs is a partly frustrated magnetic system with a Nèel temperature TN that depends on sample quality, a sample-dependent spin freezing temperature TF < TN, and magnetic hysteresis that depends strongly on preparation conditions due to ferromagnetic minority phases in disordered samples.

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