Electronic Resource
[S.l.]
:
American Institute of Physics (AIP)
Journal of Applied Physics
72 (1992), S. 218-223
ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Dielectric properties of CaNdAlO4 monocrystals, a prospective substrate material for the deposition of high-Tc superconductors, were measured with high accuracy at microwave frequencies from 8 to 40 GHz in the temperature range from 10 to 300 K by measuring the resonant frequencies of a completely filled resonant cavity. The material was found to be highly anisotropic. At 300 K it exhibits the dielectric constant along c axis ε'c = 17.68, while the dielectric constant in the a-b plane is ε'=19.62, and loss tangent tan δc (approximately-equal-to) tan δ (approximately-equal-to) 5.1× 10−4. Both ε'c and ε' depend strongly on temperature and their thermal coefficients have opposite signs, apparently a unique property of CaNdAlO4. Below 160 K microwave losses caused by electric field perpendicular to the optical c axis increase with decreasing temperature, exhibiting a maximum near 65 K followed by a minimum at 30 K. It is suggested that neodymium ions in CaNdAlO4 at lower temperatures become magnetically ordered, causing an increase of magnetic permeability μ'c (approximately-greater-than) 1 and a significant increase of magnetic losses at microwave frequencies. A crystallographic phase transition below 60 K cannot also be excluded.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.352162
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