A new family of cold conductors
A superconductor can carry electrical current without measurable resistance under suitable conditions. The 2006 study by Yoichi Kamihara and colleagues examined a layered compound called LaOFeP, containing lanthanum, oxygen, iron and phosphorus. Their measurements indicated superconducting behaviour at very low temperatures. This mattered because it pointed to an iron-based layered material family worth studying. The material is not the same as the iron–arsenic compounds reported later, and the paper did not discover superconductivity itself.
Two pieces of evidence
The team made samples and measured electrical resistance as temperature fell. They also measured magnetic response. In the reported sample the resistance dropped below the measurement limit at low temperature, and the magnetic response became diamagnetic. A measurement limit is the smallest signal that this experiment can distinguish from zero; it is more precise to report that limit than to say that every conceivable resistance was ruled out. Both types of measurement help describe the sample, but each has its own assumptions.
How cold is 3.2 kelvin?
For one sample, the paper says resistance fell below its measurement limit at about 3.2 kelvin. Kelvin measures temperature from absolute zero. To convert 3.2 kelvin to the Celsius scale, subtract 273.15: the result is approximately minus 269.95 degrees Celsius. This is a conversion of the reported scale, not a temperature someone can reach with an ordinary freezer. The paper also examined fluorine-doped material, so a reader should keep the sample and the definition of transition temperature attached to any number.
A discovery is not a full mechanism
The authors reported behaviour of particular polycrystalline samples; they did not determine a complete microscopic theory or pairing mechanism for all iron-based superconductors. A shielding estimate from a magnetic measurement is not automatically a direct map of every part of the sample. Subsequent research on iron–arsenic compounds developed a related but distinct line. The earlier discovery of copper-oxide superconductivity belongs to different authors and material; related histories should be linked without assigning the same contribution twice.
Try a source check
Find the plots of resistance and magnetic response in the paper. Ask your agent to list the sample name, what each axis measures, and whether a temperature is an onset, a midpoint or a stated measurement-limit value. Check the 3.2 kelvin conversion yourself. Then write one sentence explaining why an experimental transition does not by itself identify the microscopic mechanism. You can stop after this small source table; no laboratory work is required.
Scientific scope
The result concerns the reported polycrystalline samples and measurement conditions. Shielding fractions were estimated from susceptibility and do not directly establish perfectly uniform superconducting volume. The mechanism and pairing symmetry were not determined; the later 2008 iron–arsenic compound is a distinct result.
Read the original work
Sources and reading locations for this explanation
- Iron-Based Layered Superconductor: LaOFeP
2006 publisher record and original contribution.
- Open copy of the 2006 JACS paper
Paper figures, sample measurements and complete printed byline.
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People and systems
Yoichi Kamihara; Hidenori Hiramatsu; Masahiro Hirano; Ryuto Kawamura; Hiroshi Yanagi; Toshio Kamiya; Hideo Hosono
These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.
Research locations and affiliations
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Documented countries / regions: Japan
Japan Science and Technology Agency and Tokyo Institute of Technology, Japan. These locations are paper affiliations, not author nationalities or ownership.