Study of the eg orbitals in the bilayer manganite La2-2xSr1+2xMn2O7 by using magnetic Compton-profile measurement

From the magnetic Compton-profile (MCP) measurement, we have directly differentiated for the first time the populations in two e(g)-type orbitals (x(2) - y(2) and 3z(2) - r(2)) in a manganite. The experimental MCP's along the [001] direction for La2-2xSr1+2xMn2O7 at x = 0.35 and 0.42 are fitted by the theoretical profiles obtained from the (MnO6)(8-) ab initio calculations. The calculation confirms that the MCP clearly detects the oxygen hybridization in the e, orbitals. The e, state: is dominated by the x(2) - y(2)-type orbital with almost constant population, while the population in the 3z(2) - r(2)-type orbital decreases with increasing the hole concentration x.