IrSr2Sm1.15Ce0.85Cu

R. H. Colman

¹

,

Abbie C. Mclaughlin²

Abstract

A new iridium-containing layered cuprate material, Ir 0.825 Sr 2 Sm 1.15 Ce 0.85 Cu 2.175 O 10 , has been synthesized by conventional ambient-pressure solid-state techniques. The material's structure has been fully characterized by Rietveld refinement of high-resolution synchrotron x-ray diffraction data; tilts and rotations of the IrO 6 octahedra are observed as a result of a bond mismatch between in-plane Ir-O and Cu-O bond lengths. DC-susceptibility measurements evidence a complex set of magnetic transitions upon cooling that are characteristic of a reentrant spin-glass ground-state. The glassy character of the lowest-temperature (T g = 10 K) transition is further confirmed by AC-susceptibility measurements, showing a characteristic frequency dependence that can be well fitted by the Vogel-Fulcher law and yields a value of T f [T f log(ω)] = 0.015(1), typical of dilute magnetic systems. Electronic transport measurements show the material to be semiconducting at all temperatures, so that the CuO 2 planes are underdoped with no evidence of a transition to a superconducting state. Negative magnetoresistance is observed when the material is cooled below 20 K, and the magnitude of this magnetoresistance is seen to increase upon cooling to a value of MR = −9% at 8 K.

Mott variable-range hopping and weak antilocalization effect in heteroepitaxial Na2IrO3thin films

“…Fitting the experimental resistivity results using Eq. (1), we obtain T 0 comparable with various other transition-metal oxides [36][37][38][39][40] 045111-3 TABLE I. Na 2 IrO 3 thin films grown on YAO(001) at T ≈ 550 • C and oxygen partial pressures p 02 : Room temperature resistivity ρ(T = 300 K), ρ 0 , and T 0 are fit parameters according to Eq. (1).…”

The magnetic susceptibility on the transverse antiferromagnetic Ising model: Analysis of the reentrant behavior

“…In both cases it appears the two transition points near the second transition point the derivative dχ s /dT > 0 is positive and at high-temperature the entropy is the predominant factor and the system is then in the disordered P phase but with an AF bias due the applied fields. This is a good model that could represent multiple magnetic transitions as it is seen experimentally in some materials [13,14]. As expected, χ s increases rapidly with increasing temperature and diverges at the critical point T c and and behavior is presented as 1/T in the limit of high-temperature, as expected.…”

“…On the other hand, due to the fact that we only observed second-order phase transitions, we analysed only the Eqs. (14) and (15) in the limit of m s → 0, so as to obtain the phase diagram. So we could locate the second-order line using the fact that m A = m 0 + m s in Eq.…”

“…Another SG material that has the reentrant behaviour is the IrSr 2 Sm 1.15 Ce 0.85 Cu 2.175 O 10 [14]. The reentrant behaviour, in this compounds, it can be seen via magnetic property measurements of AC and DC susceptibility.…”

Metal-semiconductor-transition observed in Bi2Ca(Sr, Ba)2Co2O8+δ single crystals

“…16,17 The fitted parameters of these materials are summarized in Table I of supplementary material. 15 The well agreement between fitted and experimental results ( Fig.…”