Magnetism depending on carrier in (Zn,Co)O

Abstract

61.72.Vv -Doping and impurity implantation in III-V and II-VI semiconductors PACS 71.20.-b -Electron density of states and band structure of crystalline solidsAbstract -The ferromagnetic properties of (Zn,Co)O were observed by a magnetometer at low temperatures. This is, however, inconsistent with the results from the magneto-optical measurements. They reflect the presence of Co metal precipitates in (Zn,Co)O. On the other hand, the formation of Co metal precipitates was strongly suppressed by the additional Cu doping. It appears that the formation of Co metal precipitates is related to the carrier concentration in the system.

Quantum-limited metrology with nonlinear detection schemes

“…(40), but without involving the uncertainty relation in Eq. (41). Finally, the previous performance measures satisfy the following chain of inequalities [35] M ∂ M χ ∂χ…”

“…(6), the minimum uncertainty χ scales as the inverse of the number of particles N. This is usually referred to as the Heisenberg limit [28][29][30][31][32][33][34][35][36][37][38][39][40], considered the best that can be done with linear schemes. Nevertheless, other schemes where the probe state |ψ may be different for different repetitions can achieve a better use of resources, leading to uncertainties χ scaling as 1/(ν N) [40][41][42][43]. 2.…”

“…This parallels the free spectral range in spectroscopic measurements using Fabry-Perot interferometers or diffraction gratings. It can be avoided by suitably distributing the measurement into several steps of different precision [10,[40][41][42][43]61,62]. Otherwise, the signal must be known with a prior uncertainty of the order of 1/ n .…”

Cu codoping control over magnetic precipitate formation in ZnCoO nanowires

“…More recently, attention has focused around the prospect of controlling the magnetic properties of such dilute magnetic semiconductors (DMS) through codoping with non-magnetic elements such as Ga [2], Al [3] or Cu [4]. Codoping can optimize the charge carriers for enhanced ferromagnetism [5,6] and has been touted as a way to modify the tendency of the magnetic dopant to cluster into magnetic nano-precipitates [7]. While the wide focus in DMS has been on achieving robust ferromagnetism above roomtemperature [8][9][10] without such nano-precipitates [11][12][13], extremely large magnetoresistances [14] reported in such doped materials indicate a useful future as magnetic sensor elements.…”