Thickness dependent Magnetoresistance (MR) in Europium (Eu) metal Thin Films

We have prepared Eu metal thin films of different thickness under a similar condition via Pulsed Laser Deposition (PLD) technique and studied the transport properties by four-probe method using Physical Property Measurement System (PPMS). In addition to showing negative MR at high temperature and positive MR at low temperatures, thicker films exhibit hysteretic oscillation above 30 K which is believed to be associated with the re-distribution of the antiferromagnetic domains in Eu.

Thinner Eu films reveal positive MR at much lower temperature, below 30 K, and exhibit negative MR above that. The positive MR at low temperatures may originate from magnetic field induced spin fluctuation. And the negative MR at higher temperature is a result of suppression of fluctuation of the localized spins by the magnetic field. The thinner Eu films show hysteretic MR peaks in mid field range, which is a result of re-alignment and re-distribution of the antiferromagnetic domains by the magnetic fields. We will also discuss the experimental results of the Hall effect of the films.