The discovery of superconductivity is a tale of serendipity and intellect. It all began in 1911 at Leiden University in the Netherlands, when physicist Heike Kamerlingh Onnes observed an astonishing phenomenon while cooling mercury to nearly absolute zero (around - 269℃): the electrical resistance of mercury suddenly vanished at 4.2 K. He astutely recognized this as a new state of matter and named it “superconductivity.” This groundbreaking discovery earned him the Nobel Prize in Physics in 1913.
Initially, superconductivity was thought to be defined solely by “zero resistance.” It wasn’t until 1933 that German physicists Walther Meissner and Robert Ochsenfeld uncovered the second cornerstone: perfect diamagnetism, later termed the Meissner effect. They discovered that a superconductor isn’t just a perfect conductor but also a perfect diamagnet. This finding completed the definition of superconductivity and laid a solid foundation for future applications like magnetic levitation.
For decades that followed, superconductivity research seemed stuck in a “low-temperature trap.” Scientists identified various metals and alloys (such as niobium-titanium) that exhibited superconductivity, but their critical temperatures remained very low, requiring expensive and scarce liquid helium for cooling. This severely limited practical applications, confining superconductors to niche areas like specialized magnets for MRI systems and large-scale research facilities.
A major breakthrough came in 1986 when Johannes Bednorz and Karl Müller at IBM’s Zurich Research Laboratory discovered copper-oxide-based ceramics with a critical temperature of 35 K (-238℃). This shattered the “metals-only” dogma and earned them a swift Nobel Prize the following year. Subsequently, scientists like Zhao Zhongxian in China pioneered yttrium-barium-copper-oxide (YBCO) superconductors with critical temperatures reaching 77 K (-196℃), enabling the use of inexpensive liquid nitrogen for cooling. This advancement propelled superconductivity research onto the international forefront and opened doors for practical applications.
The 21st century has witnessed the emergence of iron-based superconductors (discovered in 2008) and novel systems like “magic-angle” graphene. Reports of alleged “room-temperature superconductivity” periodically ignite global interest, reflecting humanity’s enduring quest to push the temperature limits. From its accidental discovery in 1911 to the present day, the century-long history of superconductivity is a scientific epic -- evolving from chance observation to systematic exploration, and from extreme cold toward practical use -- constantly challenging the frontiers of knowledge.
