Physics – Condensed Matter – Materials Science
Scientific paper
2003-02-13
Physics
Condensed Matter
Materials Science
27 pages; 11 figures, Submitted to J.Phys:Condens Matter
Scientific paper
10.1088/0953-8984/15/19/306
All the three series of manganates showsaturation magnetization characteristic of ferromagnetism, with the ferromagnetic Tc decreasing with increasing in x up to a critical value of x, xc (xc = 0.6, 0.3, 0.2 respectively for Nd, Gd, Y). For x > xc, the magnetic moments are considerably smaller showing a small increase around TM, the value of TM decreasing slightly with increase in x or decrease in < rA >. The ferromagnetic compositions (x xc) show insulator-metal (IM) transitions, while the compositions with x > xc are insulating. The magnetic and electrical resistivity behavior of these manganates is consistent with the occurrence of phase separation in the compositions around xc, corresponding to a critical average radius of the A-site cation, < rAc >, of 1.18 A. Both Tc and TIM increase linearly when < rA > > < rAc > or x xc as expected of a homogenous ferromagnetic phase. Both Tc and TM decrease linearly with the A-site cation size disorder at the A-site as measured by the variance s2. Thus, an increase in s2 favors the insulating AFM state. Percolative conduction is observed in the compositions with < rA > > < rAc >. Electron transport properties in the insulating regime for x > xc conforms to the variable range hopping mechanism. More interestingly, when x > xc, the real part of dielectric constant (e') reaches a high value (104-106) at ordinary temperatures dropping to a very small (~500) value below a certain temperature, the value of which decreases with decreasing frequency.
Rao C. N. R.
Sudheendra L.
No associations
LandOfFree
Electronic phase separation in the rare earth manganates, (La1-xLnx)0.7Ca0.3MnO3 (Ln = Nd, Gd and Y) does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Electronic phase separation in the rare earth manganates, (La1-xLnx)0.7Ca0.3MnO3 (Ln = Nd, Gd and Y), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronic phase separation in the rare earth manganates, (La1-xLnx)0.7Ca0.3MnO3 (Ln = Nd, Gd and Y) will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-332893