2008 APS March Meeting
Volume 53, Number 2
Monday–Friday, March 10–14, 2008;
New Orleans, Louisiana
Session K1: Poster Session II: 2:00 pm - 5:00 pm
2:00 PM,
Tuesday, March 11, 2008
Morial Convention Center
Room: Exhibit Hall A
Abstract ID: BAPS.2008.MAR.K1.120
Abstract: K1.00120 : Non-Collinear Magnetic Orderings in Mott Insulators
Preview Abstract
Abstract
Author:
Alexander Bazhan
(P.L. Kapitza Institute for Physical Problems, RAS, )
Non-collinear magnetic orderings of four Cu magnetic moments in
Mott insulators Rd$_{2}$CuO$_{4 }$(R =Nd, Pr) of I4/mmm symmetry
and associated magnetic phase transitions are of interest in
studies of transformations, when correlated electron-hole
carriers are introduced in R$_{2-x}$Ce$_{x}$CuO$_{4\pm \delta }$.
Orderings are determined by thermodynamic potential in
representation by antiferromagnetic \textbf{l}$_{1}$, \textbf{
l}$_{2 }$ and magnetic \textbf{m} vectors, with orderings of
\textbf{l}$_{1 }$, \textbf{l}$_{2}$ vectors along [100] , [010]
axis,$_{ }$with values \textbf{l}$_{1}^{2 }$=
\textbf{l}$_{2}^{2 }$= 1/2 \textbf{l}$_{0}^{2}$, [1], which can
be presented as,
$\Phi \quad =$ 1/2 A( \textbf{l}$_{1}^{2 }$+
\textbf{l}$_{2}^{2})$+ 1/2 A$_{3}$\textbf{l}$_{3}^{2}$+ 1/2
B\textbf{m}$^{2}_{ }$+ 1/2 D [(\textbf{l}$_{1}$\textbf{m})$^{2}$+
(\textbf{l}$_{2}$\textbf{m})$^{2}$]+ 1/2
D$_{3}$(\textbf{l}$_{3}$\textbf{m})$^{2 }$+ 1/4 I(
\textbf{l}$_{1}^{2 }$+
\textbf{l}$_{2}^{2 })^{2}$ + 1/4 I$_{3 }$\textbf{l}$_{3}^{2
}$+1/4 E (
\textbf{l}$_{1}^{2 }-$ \textbf{l}$_{2}^{2 })^{2 }$ + 1/4 a (
\textbf{l}$_{1z}^{2 }$+ \textbf{l}$_{2z}^{2 })$ + 1/4
a\textbf{l}$_{3z}^{2} \quad -$ 1/4 b$_{2 }$[ (
\textbf{l}$_{1y}^{2 }$+
\textbf{l}$_{2x}^{2 })$ - ( \textbf{l}$_{1x}^{2 }$+
\textbf{l}$_{2y}^{2 })$ ] - 1/4 b$_{4 }$[ ( \textbf{l}$_{1y}^{2 }$+
\textbf{l}$_{2x}^{2 })^{2}$ + ( \textbf{l}$_{1x}^{2 }$+
\textbf{l}$_{2y}^{2 })^{2}$ ] -\textbf{ mH}
where \textbf{l}$_{3}$=0. Magnetic phase transitions, are
concerned with
change of \textbf{l}$_{1 }$, \textbf{l}$_{2}$ values in fields
$\sim $H$_{c1}$, $\sim $H$_{c}$, where \textbf{l}$_{1}^{2}$=0,
\textbf{l}$_{2}^{2}$=\textbf{l}$_{0}^{2}$, when field is oriented
along [100], [110] axis respectively, and next \textbf{l}$_{2
}$rotation to orthogonal to field direction in fields $\sim
$H$_{c2}$, when field is along
[110] axis. Fields H$_{c1}$, H$_{c}$, H$_{c2}$ are presented as,
H$_{c1}^{2}$=2BE\textbf{l}$_{0}^{4}$;
H$_{c}^{2}$=H$_{c1}$H$_{c2}$, if
H$_{c2}^{2}$=b$_{2}$B\textbf{l}$_{0}^{2}$; H$_{c}^{2}=\surd
$2$\cdot $H$_{c1}$H$_{c2}$ if
H$_{c2}^{2}$=b$_{4}$B\textbf{l}$_{0}^{4}$. Formation of charge
density
waves of checkerboard structure can be detected by studies of
transformation of magnetic phase transitions and fields in
R$_{2-x}$Ce$_{x}$CuO$_{4\pm \delta }$.
[1]. A. N. Bazhan, AIP Proceedings 850 (2006) 1241
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.MAR.K1.120