Magnetic properties of Mn-doped ZnO diluted magnetic semiconductors

A series of Mn-doped ZnO films have been prepared in differentsputtering plasmas by using the inductively coupled plasma enhancedphysical vapour deposition. The films show paramagnetic behaviourwhen they are deposited in an argon plasma. The Hall measurementindicates that ferromagnetism cannot be realized by increasing theelectron concentration. However, the room-temperature ferromagnetismis obtained when the films are deposited in a mixed argon-nitrogenplasma. The first-principles calculations reveal thatantiferromagnetic ordering is favoured in the case of thesubstitution of Mn$^{2 + }$ for Zn$^{2 + }$ without additionalacceptor doping. The substitution of N for O (NMn-doped ZnO, diluted magneticsemiconductors, first-principle calculationsProject supported by the ShanghaiNanotechnology Promotion Center (Grant No 0452nm071) and theNational Natural Science Foundation of China (Grant Nos 50702071 and50772122).7115A, 7550P, 7000A series of Mn-doped ZnO films have been prepared in differentsputtering plasmas by using the inductively coupled plasma enhancedphysical vapour deposition. The films show paramagnetic behaviourwhen they are deposited in an argon plasma. The Hall measurementindicates that ferromagnetism cannot be realized by increasing theelectron concentration. However, the room-temperature ferromagnetismis obtained when the films are deposited in a mixed argon-nitrogenplasma. The first-principles calculations reveal thatantiferromagnetic ordering is favoured in the case of thesubstitution of Mn$^{2 + }$ for Zn$^{2 + }$ without additionalacceptor doping. The substitution of N for O (NMn-doped ZnO, diluted magneticsemiconductors, first-principle calculationsProject supported by the ShanghaiNanotechnology Promotion Center (Grant No 0452nm071) and theNational Natural Science Foundation of China (Grant Nos 50702071 and50772122).7115A, 7550P, 7000A series of Mn-doped ZnO films have been prepared in differentsputtering plasmas by using the inductively coupled plasma enhancedphysical vapour deposition. The films show paramagnetic behaviourwhen they are deposited in an argon plasma. The Hall measurementindicates that ferromagnetism cannot be realized by increasing theelectron concentration. However, the room-temperature ferromagnetismis obtained when the films are deposited in a mixed argon-nitrogenplasma. The first-principles calculations reveal thatantiferromagnetic ordering is favoured in the case of thesubstitution of Mn$^{2 + }$ for Zn$^{2 + }$ without additionalacceptor doping. The substitution of N for O (NMn-doped ZnO, diluted magneticsemiconductors, first-principle calculationsProject supported by the ShanghaiNanotechnology Promotion Center (Grant No 0452nm071) and theNational Natural Science Foundation of China (Grant Nos 50702071 and50772122).7115A, 7550P, 7000A series of Mn-doped ZnO films have been prepared in differentsputtering plasmas by using the inductively coupled plasma enhancedphysical vapour deposition. The films show paramagnetic behaviourwhen they are deposited in an argon plasma. The Hall measurementindicates that ferromagnetism cannot be realized by increasing theelectron concentration. However, the room-temperature ferromagnetismis obtained when the films are deposited in a mixed argon-nitrogenplasma. The first-principles calculations reveal thatantiferromagnetic ordering is favoured in the case of thesubstitution of Mn$^{2 + }$ for Zn$^{2 + }$ without additionalacceptor doping. The substitution of N for O (N$_{rm O}^{ - })$ isnecessary to induce ferromagnetic couplings in the Zn-Mn-O system.The hybridization between N 2p and Mn 3d provides an empty orbitaround the Fermi level. The hopping of Mn 3d electrons through theempty orbit can induce the ferromagnetic coupling. Theferromagnetism in the N-doped Zn-Mn-O system possibly originatesfrom the charge transfer between Mn$^{2 + }$ and Mn$^{3 + }$ viaN$_{rm O}^{ - }$. The key factor is the empty orbit provided bysubstituting N for O, rather than the conductivity type or thecarrier concentration.