Three-dimensional magnetism and coupling to the conduction electrons in PdCrO2

Abstract

We report density functional calculations addressing the electronic structure and magnetic properties of delafossite PdCrO2. We find substantial magnetic interactions in the c-axis direction as well as beyond first nearest neighbors in-plane, so that PdCrO2 is a 3D frustrated antiferromagnet. We also find substantial coupling between the Cr moments and the Pd derived conduction electrons.

Magnetic structure of the conductive triangular-lattice antiferromagnet PdCrO2

“…This result suggests that a slight difference appears in the non-coplanarity of the magnetic structures between 2 K and 30 K. However, the value at 30 K is a bit larger than that at 2 K. Even if the sum of chiralities given Eq. (24) was not normalized by M 3 , the value at 2 K is smaller. If the second scenario is correct, the weight of S i · (S j × S k ) from each triangle for the UAHE is different, depending on the size of triangles or carrier mobility µ: a larger carrier mobility makes the conduction carriers interact with a larger number of spins of the non-coplanar structure 12 .…”

Collective excitations in the metallic triangular antiferromagnetPdCrO2

“…We find a noticeable discrepancy between them. We ascribe it partly to the failure of describing Pd-Pd metal-metal bonding within the shell model [13]. However, since both modes are well separated in frequencies from each other, we can identify their eigenvectors without ambiguity.…”

“…The sudden drop of the resistivity with decreasing temperature through T N is due to the suppression of magnetic-fluctuation contributions to electron transport [14]. In addition, the magnetic susceptibility data are not typical for two-dimensional spin systems: (i) the proximity of the broad maximum temperature to T N and (ii) no apparent Curie-Weiss behavior up to 450 K [9,13,15]. This signals the significance of three-dimensional and longer exchange interactions.…”

“…The intimate interplay between the spin and the electron subsystem can also account for enhanced spin-fluctuation scattering as well as interplane magnetic interactions mediated by Pd ions [13]. The sudden drop of the resistivity with decreasing temperature through T N is due to the suppression of magnetic-fluctuation contributions to electron transport [14].…”

Quantum Oscillations of the Metallic Triangular-Lattice AntiferromagnetPdCrO2

“…While most of TAFM systems are insulating, there are a few metallic systems such as PdCrO 2 [1][2][3][4][5], AgNiO 2 [6][7][8], Ag 2 MO 2 (M ¼ Cr, Mn, Ni) [9][10][11], and Fe 1:3 Sb [12]. These compounds, therefore, provide a model system to elucidate how complex magnetic order influences the nature of itinerant electrons and their transport behaviors.…”