A gateway towards non-collinear spin processing using three-atom magnets with strong substrate coupling.

A cluster of a few magnetic atoms on the surface of a nonmagnetic substrate is one suitable realization of a bit for spin-based information technology. The prevalent approach to achieve magnetic stability is decoupling the cluster spin from substrate conduction electrons in order to suppress destabilizing spin-flips. However, this route entails less flexibility in tailoring the coupling between the bits needed for spin-processing. Here, we use a spin-resolved scanning tunneling microscope to write, read, and store spin information for hours in clusters of three atoms strongly coupled to a substrate featuring a cloud of non-collinearly polarized host atoms, a so-called non-collinear giant moment cluster. The giant moment cluster can be driven into a Kondo screened state by simply moving one of its atoms to a different site. Using the exceptional atomic tunability of the non-collinear substrate mediated Dzyaloshinskii-Moriya interaction, we propose a logical scheme for a four-state memory.Information technology based on few atom magnets requires both long spin-energy relaxation times and flexible inter-bit coupling. Here, the authors show routes to manipulate information in three-atom clusters strongly coupled to substrate electrons by exploiting Dzyaloshinskii-Moriya interactions.

Absence of a spin-signature from a single Ho adatom as probed by spin-sensitive tunneling.

Whether rare-earth materials can be used as single-atom magnetic memory is an ongoing debate in recent literature. Here we show, by inelastic and spin-resolved scanning tunnelling-based methods, that we observe a strong magnetic signal and excitation from Fe atoms adsorbed on Pt(111), but see no signatures of magnetic excitation or spin-based telegraph noise for Ho atoms. Moreover, we observe that the indirect exchange field produced by a single Ho atom is negligible, as sensed by nearby Fe atoms. We demonstrate, using ab initio methods, that this stems from a comparatively weak coupling of the Ho 4f electrons with both tunnelling electrons and substrate-derived itinerant electrons, making both magnetic coupling and detection very difficult when compared to 3d elements. We discuss these results in the context of ongoing disputes and clarify important controversies.

Tailoring the chiral magnetic interaction between two individual atoms.

Chiral magnets are a promising route towards dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral magnets requires atomic-level control of the magnetic exchange interactions, including the Dzyaloshinskii-Moriya interaction, which defines a rotational sense for the magnetization of two coupled magnetic moments. Here we show that the indirect conduction electron-mediated Dzyaloshinskii-Moriya interaction between two individual magnetic atoms on a metallic surface can be manipulated by changing the interatomic distance with the tip of a scanning tunnelling microscope. We quantify this interaction by comparing our measurements to a quantum magnetic model and ab-initio calculations yielding a map of the chiral ground states of pairs of atoms depending on the interatomic separation. The map enables tailoring the chirality of the magnetization in dilute atomic-scale magnets.

Tuning emergent magnetism in a Hund's impurity.

The recently proposed concept of a Hund's metal--a metal in which electron correlations are driven by Hund's rule coupling-can be used to explain the exotic magnetic and electronic behaviour of strongly correlated electron systems of multi-orbital metallic materials. Tuning the abundance of parameters that determine these materials is, however, experimentally challenging. Here, we show that the basic constituent of a Hund's metal--a Hund's impurity--can be realized using a single iron atom adsorbed on a platinum surface, a system that comprises a magnetic moment in the presence of strong charge fluctuations. The magnetic properties can be controlled by using the tip of a scanning tunnelling microscope to change the binding site and degree of hydrogenation of the 3d transition-metal atom. We are able to experimentally explore a regime of four almost degenerate energy scales (Zeeman energy, temperature, Kondo temperature and magnetic anisotropy) and probe the magnetic excitations with the microscope tip. The regime of our Hund's impurity can be tuned from an emergent magnetic moment to a multi-orbital Kondo state, and the system could be used to test predictions of advanced many-body theories for non-Fermi liquids in quantum magnets or unconventional superconductors.

Spin excitations of individual Fe atoms on Pt(111): impact of the site-dependent giant substrate polarization.

We demonstrate using inelastic scanning tunneling spectroscopy and simulations based on density functional theory that the amplitude and sign of the magnetic anisotropy energy for a single Fe atom adsorbed onto the Pt(111) surface can be manipulated by modifying the adatom binding site. Since the magnitude of the measured anisotropy is remarkably small, up to an order of magnitude smaller than previously reported, electron-hole excitations are weak and thus the spin excitation exhibits long lived precessional lifetimes compared to the values found for the same adatom on noble metal surfaces.

[Cooperation between dermatology and psychosomatic medicine]. / Zusammenarbeit zwischen Dermatologie und Psychosomatik.

The purpose of our study was to develop the interdisciplinary cooperation between clinical dermatology and psychosomatics. The flexible adaptation of psychosomatic aspects to the current needs of dermatologists was found most important. As possible approaches, we discuss consultation and supervision, including the significance of Balint groups. On the basis of several case histories, we give some recommendations for the dermatologist interested in the psychosomatic field. We present a list of the most common dermatologic consultant diagnoses and describe some of the psychiatric manifestations.

Advanced ultrasound evaluation of fetal hydrocephaly.

Advancing technology of ultrasound imaging has unraveled numerous problems in perinatology. The 1980's is the era of high-resolution real time ultrasonography, enabling the diagnosis of fetal hydrocephaly to be made in midtrimester pregnancy even prior to the age of fetal viability. The findings obtained by full evaluation of hydrocephalic fetuses with serial ultrasounds are helpful in appropriate counseling of parents by the birth defects team and in planning the best time and management of delivery in a perinatal center. Arrest of progression of severe hydrocephaly in the second half of pregnancy prior to fetal lung maturity has been accomplished by intrauterine implantation of ventriculoamniotic shunts. The potential risk of maternal soft tissue injury from delivery of an oversized head of a severely compromised fetus can be minimized by partial and slow decompression of fetal head under ultrasound guidance using a #20 spinal needle. The influence of the recent developments on better fetal diagnosis and survival of infants with neural tube defects in 1981 was compared to that obtained during the previous five years.

Human fetal breathing movements after carbohydrate ingestion in fasting and nonfasting subjects.

Human fetal breathing movements were observed by means of the linear array real-time B-scan technique in 40 study sessions at 35 to 36 week's gestation. Fasting and nonfasting subjects received water or 75 gm of glucose orally. Fetal breathing activity, observed as movement of the chest wall, was analyzed. The data support conclusions that fetal breathing increased after maternal ingestion of glucose in both fasting and nonfasting subjects, that the absolute increases in fetal breathing were similar for fasting and nonfasting subjects, and that fetal breathing occurred more frequently in nonfasting control subjects than in fasting control subjects in the setting of the study.

Fetal breathing movements in uncomplicated pregnancies. I. Relationship to gestational age.

Fetal breathing movements occur in uncomplicated gestations. The relationship of fetal breathing movements recorded in 30 min sessions to gestational age and blood glucose levels is described. A total of 142 recording sessions were obtained from 45 gravid women with uncomplicated pregnancies from 24 to 41 weeks' gestation. There was a significant increase in the proportion of time spent in fetal breathing as gestational age increased. Glucose levels in a normal range (70 to 120 mg/100 ml) at the time of the recording sessions showed no correlation with the proportion of fetal breathing time.

Maternal ethanol ingestion and the occurrence of human fetal breathing movements.

The study of the development of fetal breathing movements in human gestation may provide an increased understanding of maturation of the functional central nervous system (CNS). In seven term pregnancies low maternal blood alcohol levels suppressed fetal breathing movements. No effects on fetal oxygenation or acid-base status were demonstrated at the low blood alcohol level. The suppression is therefore most consistent with a direct effect of alcohol on the fetal CNS. This investigation provides further support of the thesis that fetal breathing movements reflect some components of fetal CNS activity.

Antepartum fetal heart rate and uterine activity studies: I. Preliminary report of accelerations and the oxytocin challenge test.

A series of 344 antepartum fetal heart rate studies in 209 high-risk patients is described. The importance of evaluation of accelerations of the fetal heart rate as well as periodic decelerations associated with uterine activity is demonstrated. Our data suggest that the absence of accelerations of the fetal heart rate during the recording period may be associated with increased perinatal morbidity. Late decelerations may occur in the same recording session as accelerations of the fetal heart rate. The association of late decelerations of the fetal heart rate with no accelerations during the recording session is highly suggestive of increased perinatal morbidity. In high-risk patients, accelerations of the fetal heart rate and no late decelerations with uterine activity are a reassuring finding, with 91 per cent of patients showing no increased perinatal morbidity.