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We report the effect of nonmagnetic Ti4+ impurities on the electronic and magnetic properties of Sr3Ru2O7. Small amounts of Ti suppress the characteristic peak in magnetic susceptibility near 16 K and result in a sharp upturn in specific heat. The metamagnetic quantum phase transition and related anomalous features are quickly smeared out by small amounts of Ti. These results provide strong evidence for the existence of competing magnetic fluctuations in the ground state of Sr3Ru2O7. Ti doping suppresses the low-temperature antiferromagnetic interactions that arise from Fermi surface nesting, leaving the system in a state dominated by ferromagnetic fluctuations.

The preparation is described of (O' + beta)-sialon/mullite composite materials, potentially useful in the construction, aviation and metallurgical industries, by in situ carbothermal reduction nitridation of coal gangue with carbon black as reducing agent and high-purity nitrogen at 1 300, 1 400 or 1 500 degrees C in a furnace for 6 h and the effects of temperature and carbon content on the phase composition and microstructure of the materials are presented using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results show that the (O' + beta)-sialon/mullite composite material can be synthesised at 1 400 degrees C for 6 h to about 1 500 degrees C for 6 h and the conversion of beta-sialon into O'-sialon increases with increasing carbon content. O'-sialon is found to mainly exist as a sheet structure and hexagonal columns whereas beta-sialon has a needle-like structure. The generation of corundum decreases the bending strength and bulk density of the composite materials., The preparation is described of (O' + beta)-sialon/mullite composite materials, potentially useful in the construction, aviation and metallurgical industries, by in situ carbothermal reduction nitridation of coal gangue with carbon black as reducing agent and high-purity nitrogen at 1 300, 1 400 or 1 500 degrees C in a furnace for 6 h and the effects of temperature and carbon content on the phase composition and microstructure of the materials are presented using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results show that the (O' + beta)-sialon/mullite composite material can be synthesised at 1 400 degrees C for 6 h to about 1 500 degrees C for 6 h and the conversion of beta-sialon into O'-sialon increases with increasing carbon content. O'-sialon is found to mainly exist as a sheet structure and hexagonal columns whereas beta-sialon has a needle-like structure. The generation of corundum decreases the bending strength and bulk density of the composite materials.