The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

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A comprehensive review of zno materials and devices

This article discusses fluctuating order in a quantum disordered phase proximate to a quantum critical point, with particular emphasis on fluctuating stripe order. Optimal strategies are derived for extracting information concerning such local order from experiments, with emphasis on neutron scattering and scanning tunneling microscopy. These ideas are tested by application to two model systems---an exactly solvable one-dimensional (1D) electron gas with an impurity, and a weakly interacting 2D electron gas. Experiments on the cuprate high-temperature superconductors which can be analyzed using these strategies are extensively reviewed. The authors adduce evidence that stripe correlations are widespread in the cuprates. They compare and contrast the advantages of two limiting perspectives on the high-temperature superconductor: weak coupling, in which correlation effects are treated as a perturbation on an underlying metallic (although renormalized) Fermi-liquid state, and strong coupling, in which the magnetism is associated with well-defined localized spins, and stripes are viewed as a form of micro phase separation. The authors present quantitative indicators that the latter view better accounts for the observed stripe phenomena in the cuprates.

How to detect fluctuating stripes in the high-temperature superconductors

Hydrothermal growth of ZnO nanostructures

Spintronics is a multidisciplinary field involving physics, chemistry, and engineering, and is a new research area for solid-state scientists. A variety of new materials must be found to satisfy different demands. The search for ferromagnetic semiconductors and stable half-metallic ferromagnets with Curie temperatures higher than room temperature remains a priority for solid-state chemistry. A general understanding of structure-property relationships is a necessary prerequisite for the design of new materials. In this Review, the most important developments in the field of spintronics are described from the point of view of materials science.

Spintronics: a challenge for materials science and solid-state chemistry.

and Perspectives Sophie Carenco,†,‡,§,∥,⊥ David Portehault,*,†,‡,§ Ced́ric Boissier̀e,†,‡,§ Nicolas Meźailles, and Cleḿent Sanchez*,†,‡,§ †Chimie de la Matier̀e Condenseé de Paris, UPMC Univ Paris 06, UMR 7574, Colleg̀e de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France ‡Chimie de la Matier̀e Condenseé de Paris, CNRS, UMR 77574, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Chimie de la Matier̀e Condenseé de Paris, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Laboratory Heteroelements and Coordination, Chemistry Department, Ecole Polytechnique, CNRS-UMR 7653, Palaiseau, France

Nanoscaled metal borides and phosphides: recent developments and perspectives

We report a study of the magnetic properties of transition-metal doped Zn1−xTMxO (TM=Mn, Co, Fe). Polycrystalline powder samples were synthesized by both solid-state and liquid-phase reactions. From the Curie–Weiss behavior of susceptibility at high temperatures, it was found that the TM–TM interaction is dominated by antiferromagnetic coupling with effective nearest-neighbor exchange constants J=−90 to −30 K. The magnetization data measured at low temperature as a function field H are fit to a parameterized Brillouin function to obtain the effective concentration xeff of magnetically active TM2+ ions. As x increases, the fraction of magnetically active ions, xeff/x, decreases. This is ascribed to an increase in average AF interaction between doped magnetic spins as the average distance between them decreases with an increase in x.

Magnetic properties of ZnO-based diluted magnetic semiconductors

Two-step magnetic transitions: An azide-bridged 1D Mn(III) coordination polymer with a unique single end-on mode was prepared; it displayed atypical antiferromagnetic couplings and field-induced two-step magnetic transitions (see figure). The spin-canted phenomenon in the antiferromagnetic chain complex plays a pivotal role in establishing the slow magnetic relaxation.

An End‐On Azide‐Bridged Antiferromagnetic Single‐Chain Magnet Involving Spin Canting and Field‐Induced Two‐Step Magnetic Transitions

Hexanuclear, octanuclear, and decanuclear manganese metalladiazamacrocycles have been prepared by reacting a series of pentadentate ligands, N-acylsalicylhydrazides (N-(3-methylbutanoyl)salicylhydrazide (H(3)3-mbshz), N-(phenylacetyl)salicylhydrazide (H(3)pashz), N-(3,3-dimethylbutanoyl)salicylhydrazide (H(3)3-dmbshz), N-(2-methylpropanoyl)salicylhydrazide (H(3)2-mpshz), N-((R,S)-2-methylbutanoyl)salicylhydrazide (H(3)RS-2-mbshz), N-((S)-2-methylbutanoyl)salicylhydrazide (H(3)S-2-mbshz), and N-(2,2-dimethylpropanoyl)salicylhydrazide (H(3)2-dmpshz)), with manganese(II) acetate tetrahydrate. The self-assembled, supramolecular complexes assume a nearly planar cyclic structure with an -(Mn-N-N)(n) backbone and measure approximately 2.1, approximately 2.3, and approximately 2.6 nm in outer diameters for n = 6, 8, and 10, respectively. The chiralities of the manganese centers on the metalladiazamacrocycle occur in alternating ...LambdaDeltaLambdaDelta... configurations. While beta-branched N-acylsalicylhydrazides (H(3)3-mbshz, H(3)pashz, H(3)3-dmbshz) with a sterically flexible Calpha methylene group yield 18-membered hexanuclear manganese metalladiazamacrocycles of S(6) point group symmetry, alpha-branched N-acylsalicylhydrazides lead to 24-membered octanuclear manganese metalladiazamacrocycles or 30-membered decanuclear manganese metalladiazamacrocycles depending on the size of the N-acyl substituents. The alpha-branched H(3)2-mpshz ligand with the sterically least demanding isopropyl tail at the N-acyl position yields a 24-membered octanuclear manganese metalladiazamacrocycle of S(8) point group symmetry, but other alpha-branched N-acylsalicylhydrazides such as H(3)RS-2-mbshz, H(3)S-2-mbshz, and H(3)2-dmpshz lead to 30-membered decanuclear manganese metalladiazamacrocycles of S(10) point group symmetry. The magnetic properties of the metalladiazamacrocycles are characterized by a weak antiferromagnetic exchange interaction, with J(eff) = -8.5 to -3.8 K between the Mn(3+) ion spins with S = 2 in the cyclic system.

Modulation of the Ring Size and Nuclearity of Metallamacrocycles via the Steric Effect of Ligands: Preparation and Characterization of 18-Membered Hexanuclear, 24-Membered Octanuclear, and 30-Membered Decanuclear Manganese Metalladiazamacrocycles with α- and β-Branched N-Acylsalicylhydrazides

A novel S4-symmetric icosanuclear manganese metalladiazamacrocycle was synthesized using a pentadentate ligand, N-3-phenyl-trans-2-propenoylsalicylhydrazide (H3L), that has a rigid and bulky terminal N-acyl group. A 20 cyclic repeat of an--(Mn-N-N)--linkage resulted in a highly puckered diaza-bridged 60-membered icosanuclear metallamacrocycle. The steric interaction between the ligands in the cyclic system leads to five consecutive Mn(III) centers in a chemically different--(Mn(A)Mn(B)Mn(C)Mn(D)Mn(E))--environment, with the chiralities of the metal centers being in a rather complicated--(LambdaLambdaDeltaLambdaLambda)(DeltaDeltaLambdaDeltaDelta)--sequence.

Steric control of a bridging ligand for high-nuclearity metallamacrocycle formation: a highly puckered 60-membered icosanuclear metalladiazamacrocycle.

We report on helical coordination networks that were prepared using a hexanuclear manganese metallamacrocycle as a helical tecton. We were able to prepare the three-dimensional helical coordination networks using a hexanuclear manganese metallamacrocycle, [Mn6(lshz)6], as a helical tecton, where N-lauroyl salicylhydrazide (H3lshz) was used as the primary building unit to generate the helical tecton as a secondary building unit. While the 41/43 screw symmetry-linked helical coordination network was obtained when the primary building units had an N-acetyl group, both the 31/32 screw symmetry-linked and the 41/43 screw symmetry-linked helical coordination networks were obtained simultaneously in the same batch when the primary building unit had a long alkyl N-lauroyl group at the N-acetyl site.

Byoung Jin Suh

Papers

Magnetic properties of ZnO-based diluted magnetic semiconductors

An End‐On Azide‐Bridged Antiferromagnetic Single‐Chain Magnet Involving Spin Canting and Field‐Induced Two‐Step Magnetic Transitions

Modulation of the Ring Size and Nuclearity of Metallamacrocycles via the Steric Effect of Ligands: Preparation and Characterization of 18-Membered Hexanuclear, 24-Membered Octanuclear, and 30-Membered Decanuclear Manganese Metalladiazamacrocycles with α- and β-Branched N-Acylsalicylhydrazides

Steric control of a bridging ligand for high-nuclearity metallamacrocycle formation: a highly puckered 60-membered icosanuclear metalladiazamacrocycle.

Three-dimensional helical coordination networks of a hexanuclear manganese metallamacrocycle as a helical tecton.