Far-infrared absorption of La1-xCaxMnO3-y at high pressure.
The first far-infrared absorption spectra of manganite samples at pressures P up to 10 GPa were obtained on La1-xCaxMnO3-y by use of synchrotron radiation. For x=0.25 and 0.20 (y=0), P promotes partial metallization at room temperature through a strong reduction of the insulating gap. An x=0.20 sample with y=0.08 does not show any charge delocalization effect up to 10 GPa. An Urbach-like model of disordered Jahn-Teller wells is shown to well fit the far-infrared band edge and allows one to obtain a reliable pressure dependence of the energy gap.
Sacchetti
A
A
Coherentia CNR-INFM and Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 2, I-00185 Roma, Italy.
Guidi
M Cestelli
MC
Arcangeletti
E
E
Nucara
A
A
Calvani
P
P
Piccinini
M
M
Marcelli
A
A
Postorino
P
P