Dielectric properties of CaNdAlO4at microwave frequencies
| Autor: | S. J. Lewandowski, J. Konopka, Ingo Wolff |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 72:218-223 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.352162 |
| Popis: | 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 e’c = 17.68, while the dielectric constant in the a‐b plane is e’=19.62, and loss tangent tan δc ≂ tan δ ≂ 5.1× 10−4. Both e’c and e’ 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 permeabili... |
| Databáze: | OpenAIRE |
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