Intrinsic Complex Vacancy-Induced d0 Magnetism in Ca2Nb2O7 PLD Film

Introducing magnetism into the ferroelectric Ca2Nb2O7 with high Curie temperature can make it a potential multiferroic material at room temperature. Stoichiometric Ca2Nb2O7, nonstoichiometric Ca1.9Nb2O7-δ and Ca2Nb1.9O7-δ single phase films were deposited on STO (110) substrate by pulsed laser deposition under appropriate conditions. The films were characterized by XRD, FE-SEM, Element mapping and XPS. Both stoichiometric Ca2Nb2O7 and Ca1.9Nb2O7-δ films were diamagnetic in the magnetic measurement and ab initio calculations, while the Ca2Nb1.9O7-δ film with the complex vacancy of VNb+O exhibited ferromagnetic behavior at room temperature, with the saturated magnetization of 3.6 emu/cm3. Calculations on the Ca2Nb2O7 (010) surface indicate that the VNb+O can induce spin polarization on the residual O atoms around the Nb vacancies, and the system was most stable when the Nb and O vacancies were the 4th nearest-neighbored, with FM coupling energetically more stable than the AFM coupling. Our work verified experimentally and theoretically the feasibility of introducing ferromagnetism into Ca2Nb2O7 film by the intrinsic complex vacancy of VNb+O.

Extremely large d0 magnetism in krypton implanted polar ZnO films

Magnetization is produced in samples of O-polar ZnO after implantation of krypton ions.

The effect of oxygen vacancy on holes-induced d0 magnetism in CaTiO3 and CaZrO3

Using the first-principles calculations, the holes-induced [Formula: see text] magnetism associated with oxygen vacancy [Formula: see text] in [Formula: see text] and [Formula: see text] has been investigated. To obtain holes, the divalent calcium and tetravalent IVB-group ions are replaced respectively by the monovalent alkali, IB-group and trivalent III-group ions. It is found that the [Formula: see text] can enhance the magnetic moment of few acceptors-doped [Formula: see text], whereas it enhances the magnetic moment in most acceptor-doped [Formula: see text] except for La doping. Mainly, it is because the [Formula: see text] gives rise to no gap-states in [Formula: see text] but generates gap-states in [Formula: see text]. Based on the similar effect of [Formula: see text] on the band structure in [Formula: see text] or in [Formula: see text] (X = Ca, Sr, Ba), we suggest that there exists a similar effect of [Formula: see text] on [Formula: see text] magnetism in acceptor-doped alkaline titanium (zirconium) perovskites.