Magnetic property investigations on ZnMnO

There have been controversial reports about the type of magnetic coupling and hence ferromagnetism in ZnMnO. We have investigated the magnetic properties of ZnxMn1−xO layers grown by Molecular Beam Epitaxy (MBE) on sapphire substrates. At first sight, the investigated ferromagnetism in our ZnMnO layers deposited on Al2O3 substrates seemed trivial, but the results of extensive analyses of the layers and also data from the Al2O3 substrates used strongly indicate that the influence of the substrate on magnetic property measurements needs to be considered when confirming ferromagnetism in Mn-doped ZnO layers. Our ZnMnO layers showed a paramagnetic behaviour.